過去進行時的結構及句型變化

過去進行時由"was / were + 現(xiàn)在分詞"構成。如：

I was doing my lessons then. 那時，我在做功課。

We were cleaning the house. 我們在打掃房子。

過去將來時態(tài)的肯定句、否定句和疑問句形式：

肯定句例句：I was walking down the street when a UFO landed.

否定句例句：I wasn’t walking down the street when a UFO landed.

一般疑問句例句：Were you walking down the street when a UFO landed?

特殊疑問句例句：What were you doing when a UFO landed?