用在一般現(xiàn)在時，現(xiàn)在完成進行時，過去完成進行時。

　　例句與用法:

　　1.I've kept on thinking about that all the time.

　　我一直惦記著這件事。

　　2.In his job he's rubbing shoulders with film stars all the time.

　　他在工作中一直與電影明星有來往。

　　3.Then the scales fell from my eyes:he had been lying all the time.

　　我恍然大悟:他一直在撒謊。