be的过去式是什么？

be 是系动词 ，一般现在时的情况下 有3种“ am ,is ,are ”。“am,is ”的过去式是" was ",“are”的过去式是"were"。

be过去分词都是been。

is例句：He is good boy.他是个好孩子。

am例句：I am a teacher.我是一名老师。

are例句：we are friends.我们是朋友。

was例句：The building was constructed from the design of that architect.这幢大楼是按那位建筑师的设计建造的。
                                       

were例句：If I were you, I would have failed. 如果我是你，我可能会失败的。

been例句:Those rooms have been assigned to us. 那些房间已经分配给我们。