初中学的内个过去进行时语法的内个怎么说

表示过去某一时刻正在进行的动作，或者正在做的事情。
形式：was（用于单数人称主语后面）/were（用于复数主语人称后面）+doing
i was sleeping at then.
they were playing computer games when i came in.

过去进行时是was/were doing
和to do sth好像不沾边。