have是什么时态的词

　　例句：

　　This is too big ─ have you got a small one?

　　这个太大——有没有小的？

　　The latest model has over 100 new features.

　　最新的款式有100多种新特色。

　　The two groups of children have quite different characteristics.

　　这两组儿童具有截然不同的特点。

　　Now she won't have to go out to work any more.

　　现在她不必再出去工作了。

　　There have been many changes in recent years.

　　近几年发生了许多变化。