have加过去式是什么时态

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。

Call me if you have any problems regarding your work.

你如果还有什么工作方面的问题就给我打电话。

No new SARS cases have been reported in the region.

该区没有新增非典型肺炎病例。

You will always have the bad as well as the good in the world.

人生在世总是有苦有甜。