一件事如果发生在过去 动词就用过去式
就是把一般现在时的do(/does) go(/goes) be(am/is/are)换成did went was(/were)
例句：
Where did you go yesterday?你昨天去哪儿了?
I went to school yesterday.我昨天去学校了.
I was in school yesterday.我昨天在学校.