描写海豚的高中英语作文

描写海豚的高中英语作文（精选22篇）

　　在日常的学习、工作、生活中，大家都有写作文的经历，对作文很是熟悉吧，作文是由文字组成，经过人的思想考虑，通过语言组织来表达一个主题意义的文体。作文的注意事项有许多，你确定会写吗？以下是小编为大家整理的描写海豚的高中英语作文，欢迎大家分享。

　　描写海豚的高中英语作文 1

　　Hopefully you already know that dolphins are not fish. Dolphins are warm blooded mammals like us. They breath air through a nostril on the top of their heads called a blowhole. Because dolphins breath air, they must surface periodically. Fish, however, breath by using gills underwater, and therefore do not need to surface. Many fish also have scales, which dolphins do not have. Instead, the skin of a dolphin feels rubbery. A layer of fat, called blubber, under their skin keeps them warm. The locomotion of fish and dolphins is also different. Fish swim by moving their tails from side to side (horizontally). However, dolphins swim by moving their tails up and down (vertically).

　　How many kinds of dolphins are there?

　　This question will probably never be answered correctly. As humans, we want to put everything we know of into a group. Some people like large groups with some variation and others like small, precise groups. Not everyone agrees about what marine dolphins deserve their own species name and what ones do not. I currently have 32 species of marine dolphins listed. I am pretty sure that this covers all the species accurately. Most people agree that there are six species of porpoises and five species of river dolphins

　　Dolphins can understand and interpret some words and actions, they cannot understand us word for word like in the TV show. Even though dolphins may not understand us completely, they might have their own languages. In fact, many people believe that dolphins communicate with languages.

　　描写海豚的高中英语作文 2

　　Dolphin, bodily form looks like the fish, the mouth is thin and long, upper and lower jaws have 46- 6 sharp and thin teeth respectively, the body is thin and long , generally about 2- 2. meters long. The back in the shape health of streamline, the dorsal fin with sickle form . The back is greyish black, the belly is white, the place close to head of belly has a pair of pectoral fins. Theweight is between 100- 20 kilograms. Although its mouth is kissed long, there are so many teeth in the mouth, it cant chew the food , just consume small fish , shrimp , cuttlefish ,etc..

　　描写海豚的高中英语作文 3

　　The Dolphin is one of the most precious animals. Their bodies are very long. Dolphins live in the sea. They live on fish, shrimps and so on.

　　Dolphins are very friendly and peaceful. They never attack people. Instead, they have saved many people in danger. Dolphins are very clever.

　　People often train teem so that they can give a dolphin show which brings people a lot of happiness and joy.

　　描写海豚的高中英语作文 4

　　Dolphin In the vast ocean live many creatures with great intellectual and physical capacities.

　　Dolphin is one of those great creatures, whose capacities to think and move at an astounding rate puzzle those who study their behaviors.

　　Dolphins possess something that makes them different from all the other sea creatures.

　　It is not strength or speed but the size of their brains.

　　Dolphin s brain is almost the same size as that found in the human head.

　　They live for a ling time. Dolphins babies are born in the water.

　　They can grow up to three and a half meters long.

　　Dolopins use sound to help them find their way, look for their food and talk witheach other.

　　Sound is just like their eyes and mouths.

　　描写海豚的高中英语作文 5

　　Dolphin, bodily form looks like the fish, the mouth is thin and long, upper and lower jaws have 46- 6 sharp and thin teeth respectively, the body is thin and long , generally about 2- 2. meters long.

　　The back in the shape health of streamline, the dorsal fin with sickle form .

　　The back is greyish black, the belly is white, the place close to head of belly has a pair of pectoral fins.

　　Theweight is between 100- 20 kilograms.

　　Although its mouth is kissed long, there are so many teeth in the mouth, it cant chew the food , just consume small fish , shrimp , cuttlefish ,etc..

　　描写海豚的高中英语作文 6

　　In the vast ocean live many creatures with great intellectual and physical capacities. Dolphin is one of those great creatures, whose capacities to think and move at an astounding rate puzzle those who study their behaviors, Dolphins possess something that makes them different from all the other sea creatures. It is not strength or speed but the size of their brains. Dolphins brain is almost the same size as that found in the human head. They live for a ling time.

　　Dolphinsbabies are born in the water. They can grow up to three and a half meters long.

　　Dolopins use sound to help them find their way, look for their food and talk with each other. Sound is just like their eyes and mouths.

　　描写海豚的高中英语作文 7

　　Dolphin, bodily form looks like the fish, the mouth is thin and long, upper and lower jaws have 46- 6 sharp and thin teeth respectively, the body is thin and long , generally about 2- 2. meters long. The back in the shape health of streamline, the dorsal fin with sickle form .

　　The back is greyish black, the belly is white, the place close to head of belly has a pair of pectoral fins. Theweight is between 100- 20 kilograms. Although its mouth is kissed long, there are so many teeth in the mouth, it cant chew the food , just consume small fish , shrimp , cuttlefish ,etc..

　　描写海豚的高中英语作文 8

　　the vast ocean live many creatures with great intellectual and physical capacities.Dolphin is one of those great creatures,whose cap-acities to think and move at an astounding rate puzzles those who study their behaviors.Dolphins possess something that makes them different from all the other sea creatures.It isnt strength or speed but the size of their brains.Dolphins brain is almost the same size as that tound in the human head.They live for a long time.Dolphinsbabies are born in the water.They can grow up to three and a half meters long.Dolopins use sound to help them find their way,look for their food and talk with each other.Sound is just like their eyes and mouths.

　　描写海豚的高中英语作文 9

　　In the vast ocean live many creatures with great intellectual and physical capacities.Dolphin is one of those great creatures,whose capacities to think and move at an astounding rate puzzle those who study their behaviors.

　　Yesterday I went to the the aquarium to see my favorite animal-dolphins.According to the the narrator of the aquarium,I learnt a lot about the doiphin.It is one of the most precious animals.A dolphins brain is almost the same size as the human head.They can live for a long time.Dolphins babies are born in the water.They can grow up to three and a half meters long.Dolphins use sound to help them find their way,look for their food and talk with each other.They live on fish,shrimps and so on.

　　Dolphins are very clever.They give us a show which brings us a lot of happiness and joy.And I was thrilled because there was also an interaction between the dolphins and I.

　　Dolphins are our good friends.As a student,I hope more and more people should take actions to protect dolphins.

　　描写海豚的高中英语作文 10

　　Dolphin is a kind of animal.They live in the sea.You can also sea them in some parks.They are very clever,and people can teach them to play or act.

　　Dolphin babies are born in the water. They can grow up to three and a half meters long.

　　Dolophin use sound to help them find their way, look for their food and talk with each other. Sound is just like their eyes and mouths.

　　描写海豚的高中英语作文 11

　　One day Mr. Green, the science teacher, asked his class, "What do you want to be when you grow up?"

　　"I want to be a dolphin trainer like my uncle," Mike answered.

　　"Why do you want to be a dolphin trainer?" asked Mr. Green.

　　"Because Im interested in dolphin language."

　　"Dolphin language? Tell us more."

　　"All right," answered Mike, "My uncle tells me that dolphins are very clever. One day my uncle saw a sick dolphin in the pool. It couldnt come up for air. So it whistled to the other dolphins for help. They came to their friend and made some strange sounds. They looked sad. Then together they pushed the sick dolphins head up above the water. Soon it got well."

　　"Some scientists once said to my uncle, If you live with a dolphin and talk to it all day, maybe you can teach it some words. My uncle decided to do that. He lived with a dolphin. The dolphin loved to play ball so he decided to teach the word ball first. He threw a ball to the dolphin and said the word ball many times. Soon the dolphin started to say the word."

　　Kate asked, "How do they make sounds?"

　　Mike didnt know.

　　"They make sounds through blowholes in their heads," said Mr. Green. "Scientists know a little about dolphin language, but they have a lot more to learn."

　　"Thats why I want to be a dolphin trainer," said Mike.

　　描写海豚的高中英语作文 12

　　In the aquarium, there are two dolphins that I will never forget.

　　During the summer vacation, we went to the aquarium in Xiamen, where various types of fish caught my attention and the diverse underwater creatures dazzled me. Finally, we arrived at the Dolphin Home, where there were only two dolphins in the pool. A keeper was constantly teaching them how to jump up and pick up food, and these two cute guys were performing along with the keepers movements.

　　At halftime, we approached the pool and two dolphins were not afraid at all when they saw us. Instead, they swam to the edge of the glass wall near us. I placed my hand on the glass, and a dolphin even touched it with its mouth through the glass, as if showing goodwill towards me.

　　At this moment, I observed these two white little elves better. They look similar, with spindle shaped bodies and milky white skin that seems to be coated with a layer of lubricant, incredibly smooth. When the pointed mouth is opened, two rows of fine teeth can be seen up and down, and big eyes grow at both ends of the mouth, with clear black and white, charming and charming.

　　Dad took a pack of dolphins favorite fish from the keeper and let us feed it.

　　The dolphins in the water seemed to know that someone was going to feed them and immediately stopped swimming.

　　I grabbed a small fish and threw it forcefully into the pool. The nearby dolphin immediately jumped up, caught the fish, and swallowed it in one gulp. After finishing, it swam leisurely again, as if I could see the satisfaction and joy in its eyes.

　　Watching the keepers training dolphins to touch peoples hands with their mouths, I also want to give it a try. We took a wooden board and placed it less than ten centimeters above the water surface. The dolphin seemed to have received the message and quickly swam over, sometimes using its head to touch it, and sometimes using its mouth to touch it.

　　Dolphins are really cute and spiritual animals, they are so adorable!

　　描写海豚的高中英语作文 13

　　Today, a group of reporters from Qianshan Evening News Century Star visited the famous Hong Kong Ocean Park and spent three happy hours there. There, I saw a show of cute dolphins and seals performing, saw many cute jellyfish, and even played a very exciting "surfing car". Ocean Park is truly a place full of fun!

　　When we entered the Ocean Park, the first place we went was the "Jellyfish Kaleidoscope". In the "Jellyfish Kaleidoscope", I saw various rare jellyfish. They swim gently in the water, occasionally poking their heads over to take a look, as if welcoming us distant guests from the north. Unconsciously, we have already walked out of the "Jellyfish Kaleidoscope", but I am still intoxicated by that wonderful landscape, as if I have also turned into a jellyfish, greeting those tourists

　　After the "Jellyfish Kaleidoscope", we went to the "Chinese Sturgeon Museum" and then came to the "Ocean Theater" to watch a performance. In the performance, an audience member was actually afraid of seals! As he shook hands with the seal, he cautiously walked up to it, then lightly touched its hand and walked away. When kissing the seal, he actually fell into the water out of fear! Fortunately, a dolphin in the water saved him who couldnt swim and safely brought the audience to the ground. Afterwards, the dolphins performed "water hurdles" (jumping water column) for us, winning cheers on the field.

　　In the ocean park, words like "protect the ocean, protect marine animals" can be seen everywhere. When I grow up, I must become an animal protector and cherish the cute little animals!

　　描写海豚的高中英语作文 14

　　There is an animal that lives in the ocean, which is the most familiar animal to humans. It is intelligent, clever, and very likable. Do you know what animal this is? This is the dolphin.

　　It is a relatively small whale with nearly 62 species, and I will introduce a few of them next. Black and white dolphin: The Atlantic black and white dolphin, also known as the New Southwest dolphin, is a second-class protected animal in China. It feeds on small fish. Its back is black and its abdomen is white. Grey dolphin: From a side view, it resembles a pilot whale and lives in temperate and tropical waters around the world. There are many types of dolphins, and I wont introduce them one by one.

　　Most dolphins have a smooth and flowing body shape, with some dolphins having eye-catching patterns and others having consistent patterns. The facial depression of the dolphin skull is wide, and the posterior end of the maxilla extends from the beak. The scale bone zygomatic process is small and covered by the enlarged maxilla and frontal bone, and the beak shape varies from wide to narrow. This is the appearance of dolphins.

　　In 1949, the wife of a lawyer in Florida, USA, revealed in the journal Natural History her peculiar experience of being rescued from drowning at sea: while swimming at a beach, she suddenly fell into an underwater undercurrent, and rows of surging waves hit her. Just as she was about to faint, a dolphin swam quickly and gave her a sudden push with its pointed beak, followed by several more until she was pushed into shallow water. The woman woke up and looked around, wanting to see who had saved her. However, there was no one on the beach, only a dolphin playing in the water not far from the shore. This kind of story has happened many times, and from these stories, I have seen the intelligence and cleverness of dolphins.

　　Dolphins have a friendly appearance and playful personality, and have always been very popular in human culture.

　　描写海豚的高中英语作文 15

　　Hainan is a place with beautiful and pleasant scenery, including the ends of the earth, Savage Valley, and my most unforgettable place, the Dolphin Aquarium.

　　There is a large pool in the middle of the dolphin house, surrounded by an eight story stand where we can sit and watch cute dolphin performances. I saw two big dolphins swimming slowly in the swimming pool, as if taking a walk. When we were all sitting in the stands, the administrators uncle said, "The dolphins will perform later." I happily replied, "Yeah!" After a while, the hosts aunt said, "The dolphin performance is starting now! Lets do the first thing: the dolphin heads the ball." An uncle threw the ball into the water, and a dolphin jumped out and held the ball. The host said, "His name is Ding Ding, a dolphin who loves beauty. Now lets move on to the second task: dolphin drilling." The uncle took out a hula hoop, and another dolphin jumped out of the water and crawled over. The host said, "This is called a ball, the coolest dolphin. Lets take a look at the third item. The ball and Tintin paddle together. Please have a child sit on the boat and try it out. Which child will come up?" At this moment, I only heard an uproar in the stands, and many children raised their hands, and I also raised my hands high. How I long to be selected into my ranks. Fortunately, the host aunt let me go up. I jumped up from the chair happily and bounced over. The administrator uncle helped me board an inflatable boat supported by two dolphins. Then I looked at the stands, wow! There are so many people! I saw them all pointing their cameras at me, and I felt like a celebrity. Two dolphins held me and circled around the pool, the inflatable boat they were holding swaying. I held onto the armrest tightly with both hands, still feeling a little scared. During the transfer period, many uncles and aunts took photos of my little star.

　　Hainan is really beautiful! I love Hainan, and what I remember more is the beautiful dolphin aquarium!

　　描写海豚的高中英语作文 16

　　I love dolphins, they are friends of humans.

　　I love dolphins, they are my little companions. There are plush dolphins hanging on the wall of the room; There is a plush dolphin taller than me on the bed; There is a dolphin piggy bank on the table... and I have to hold my little dolphin while sleeping

　　I have gained a better understanding of dolphins from the extracurricular reading materials my mother bought for me. Dolphins are friends of humans, and they are very willing to interact with humans. Dolphins are a type of intelligent and highly intelligent animal. They do not flee from people like timid animals in the forest, nor do they show their teeth and claws like wild beasts in the deep mountains and forests. Dolphins always appear very gentle and approachable to humans, and sometimes even more friendly to humans than dogs and horses. I heard that some children with depression have become more cheerful by befriending dolphins!

　　During the May Day holiday, my parents and I went to the Beijing Aquarium to see real dolphins and even watched their performances! They performed exceptionally well.

　　As soon as a little dolphin named "Teng Teng" appeared, I was immediately attracted by its beautiful singing and graceful dancing. More adorable than in the picture, it was seen flapping its front fins on the water surface, creating many splashes of water. "Okay!" All the audience present cheered. The most interesting thing is that the little "Teng Teng" actually used its pointed mouth to shake the hula hoop. Just like how my mom usually shakes her hula hoop, but she has to use her waist and her mouth isnt that long; Another thing is jumping in circles, Xiaoteng leaped out of the water like an arrow leaving the string, drilled through the circle, and drew a wonderful arc behind. At high altitude, the dolphins leaped out of the water and topped up a red balloon that was over five meters high in the air, showing us their excellent jumping ability.

　　Seeing the performance of dolphins, I feel even more adorable and love them even more.

　　描写海豚的高中英语作文 17

　　In the vast ocean, there is an incredibly cute social animal - dolphins. They come in blue and gray, but my favorite is still the pink dolphins from Amazon.

　　Why is pink dolphin my favorite? Because they are very special, pink in color, and also very rare in the ocean, they are known as "national first-class protected animals".

　　The body of the pink dolphin is 2 meters long! The weight is also 200 pounds! Its whole body is almost pink, only a part is light yellow. When it jumps, it looks like a pink crescent moon, very beautiful! Its mouth is pointed, like an eggplant; The eyes are round, small, and watery, similar to other dolphins.

　　Because they are social animals, it is easy for them to prey on delicious small fish and shrimp, and they often jump out of the water. Under the sunlight, they may also appear in colorful rainbows. How beautiful this scene is!

　　They are still lifeguards in the sea. It is said that there was once a group of tourists sailing on a cruise ship, and their dog was accidentally swept into the sea by a huge wave, but the owner was unaware. But at this moment, a shark was nearby and gradually wanted the little dog to approach silently. The little dog struggled desperately in the sea to swim towards the ship, but the ship gradually drifted away and could never catch up. Just as the shark opened its bloody mouth, a pink dolphin suddenly darted out of the water and pushed the shark away with a sharp and powerful beak. It put the puppy on its back and carried it back to the boat, dancing and performing various movements for it... There are many stories to tell.

　　Pink dolphins are deeply loved by me, and also because they are talented singers with musical talent and acrobats with acrobatic talent. They are really amazing!

　　描写海豚的高中英语作文 18

　　Its another annual National Day, and my parents took me and my younger brother to the Ocean World on Tianzhu Mountain to watch dolphin performances.

　　As soon as I entered, I saw a mysterious tunnel with glass window exhibition cabinets on both sides, which looked extremely mysterious. Even my usually serious mother was very excited: Through this tunnel, we can see dolphins! Hearing this, I couldnt wait to jump forward like a little monkey.

　　Finally squeezed into the dolphin performance area, we quickly found a few seats and sat down. Just as I sat down, the broadcast started: "Please find your seats as soon as possible, the exciting dolphin performance is about to begin After a rustling sound, most of the audience present sat up and the broadcast started again: "The dolphin performance has officially begun

　　Accompanied by cheerful music, several animal trainers ran out of the backstage with light steps, each holding a small bucket for an unknown purpose. Then, the gates connecting to other swimming pools opened, and lively dolphins rushed out, causing bursts of cheers.

　　Firstly, the dolphins performed a top ball for us. I saw the animal trainers throwing several small balls of different colors into the pool together, and well-trained dolphins spinning around with their respective small balls. Among them, there is one dolphin that is the most powerful! It first throws the ball with its tail, then steadily catches it with its head, and finally gives the ball to its trainer. The animal trainer took out a fish from a small bucket placed on the ground and threw it to the dolphin who had performed exceptionally well as a reward. I suddenly realized that the bucket was filled with food for the dolphin!

　　Later, the dolphins and trainers continued to perform many incredible shows for us, such as dolphins drilling hula hoops and people surfing on the backs of dolphins

　　After returning home, I was still reminiscing: dolphins are really cute!

　　描写海豚的高中英语作文 19

　　A pair of red eyes, a pair of invisible small ears, a round head, a big mouth, small and neat teeth, protruding forehead, gray front fins, middle fins, tail fins, outlining a streamlined body, this is the clever and powerful little elf - dolphin.

　　Dolphins are mammals that enjoy living in groups and feed on small turtles, thieves, shrimp, and crabs. Hearing is the most sensitive sense of dolphins, which is relied upon for hunting, swimming, and playing. In the entire animal kingdom, the dolphins brain is the most developed. Its brain is composed of two completely separated parts, one of which works while the other rests fully. Therefore, it can stay up all night, even if it closes its eyes to rest, it can still avoid danger to the greatest extent possible.

　　The clever and clever dolphin is destined to be a genius performer. Of course, this also requires strict training from trainers. In order to bring more exciting performances to the audience, they repeat actions such as jumping and drilling circles every day. If they perform well during training, they will receive rewards and are their favorite little fish. During formal performances, they also bring their specialty, which is singing,

　　Nowadays, dont we humans also have a special admiration for dolphins? Everyone is learning dolphin sound.

　　Dolphins, human friends, bring endless laughter to humans, but their living environment is under great threat. Without hesitation, humans dump various types of garbage, industrial waste gas, wastewater, pesticides, and oilfield waste into the ocean, causing the marine environment to gradually deteriorate. Dolphins are facing a catastrophic disaster. Let us join hands to protect the environment and create a beautiful home for our little elves!

　　描写海豚的高中英语作文 20

　　On this day, I saw a dolphin on TV, performing various skills in the aquarium and becoming a beloved little star. So, I had the idea of becoming a dolphin. I fell asleep as I watched.

　　Suddenly, I woke up from my dream and found myself surrounded by a sea of blue, with colorful fish everywhere, ranging from a small turtle to a whale. Through the reflection of glass, oh my god! I actually turned into a dolphin! Big and round eyes, pointed mouth, long body... I just realized that this is an oceanarium.

　　Suddenly, a trainer shouted at us, Training! Who will come first? Everyone stepped back, were they all afraid of training? Perhaps you want me to try. I was like an arrow leaving the string, the first to surface and enthusiastically called out to the trainer a few times. The trainer led me to the training pool and took out a large circle for me to jump. I struggled to "drive" my new body and jumped onto the circle, but I didnt jump over. The trainer took out a whip and beat me hard. When I failed every training project, I was already covered in bruises. The trainer angrily walked out of the door and made a phone call.

　　The next day, a group of people rudely caught me and threw me onto a large truck. Where are they going to take me? I was still optimistic, thinking that I might be released or sent to a zoo for people to watch, so that I wouldnt die tragically on the streets. However, the reality is always disappointing. What awaits me is a sharp kitchen knife

　　Ah! I woke up from my dream, luckily! Im still a little boy. Human beings, please do not indiscriminately kill animals. Take good care of and protect animals!

　　描写海豚的高中英语作文 21

　　My two lobed tail often swings up and down, and my light blue and even body forms a convex shape, which is both moving and beautiful. My pointed dorsal fin makes me elegant and charming, and my small head carries a lot of knowledge. I am smart and small, and my dark and flickering big eyes make me even cuter. you re right! This is me, a little dolphin named Huanhuan!

　　Our dolphin family has several natural enemies, such as killer whales, sharks, and so on.

　　One day, three of us little dolphins were playing a game of throwing sea cucumbers. Suddenly, a little friend disappeared, leaving only a large area of blood. I looked up in panic as a huge killer whale tore at my friends body. Faced with this behemoth, we are no match for him at all. Both the other little dolphin and I have only one word in our minds - escape! We swam quickly, but the killer whale quickly turned around and chased after us.

　　With a loud bang, we were dragged to the surface by a force. Ah。 We were caught in a net and instantly pulled up to the surface of the water, slowly moving towards the big ship. We were pulled onto a large ship and roughly thrown into a water tank. I didnt care about the pain and used the force of breastfeeding to desperately hit the lid of the box. Suddenly, the lid of the box was opened and the electric baton reached out to us like a magic claw

　　When we woke up, we were in a large water tank. oh So we arrived at the aquarium. We called for help from the passing humans through the glass, Save us! Save us! But they just looked at us with curious eyes, and the children pointed at us.

　　Human beings! Dont capture wild animals, its disrupting the ecological balance of nature! Please let us return to our own home as soon as possible!

　　描写海豚的高中英语作文 22

　　Henry is a cute and clever little dolphin, he is my baby.

　　I got it during a voyage. When it was discovered, it had just been born and its body was still very small. Its tail was red, as if it was bleeding. I quickly brought it up and invited marine biologist Amanda and veterinarian Karen from the ship. Karen bandaged the wound. The next day, I named it Henry and let it temporarily live in a 100 meter long and 80 meter wide ocean pool, feeding it small fish every day. Gradually, it became familiar to me. Every day when I call Henry, he jumps out of the water.

　　When I got off the ship, I found a large water tank that Amanda used to raise marine creatures and pulled it away with a truck. When I got home, I added salt to the swimming pool in the yard in proportion and released Henry inside. I will play with Henry every day from now on.

　　Days passed by day by day, and Henry grew up. As I was about to let him go back, I suddenly thought to myself, would Henry be killed by a shark when he was adopted by me at a young age? With this in mind, I quickly called robotics expert Miles and asked if he could make a shark robot to experiment with. He readily agreed.

　　Three days later, he was holding a robot that looked very much like a shark. I pressed the button and the "shark" immediately started moving, which scared me a lot. During those days, I was training Henry all the time. "Henry has finished training, its time to see the results," Amanda said. It turned out that he let a real shark in, and I was very scared... I saw Amanda press the remote control on her hand, and a door on the wall opened, and a fierce shark rushed in! I saw Henry wag his tail and fiercely hit the shark. He made a quick turn and collided with the sharks head, killing it. This series of actions only lasted for 38 seconds!

　　Henry can be released now, and I bid him farewell with reluctance. He turned around and looked at me, slowly swimming towards the distance