什么情况下用be动词的过去式?

英语小辈：
一般过去时：用动词过去式
如go,work,study...
I went to school .
I worked in the daytime.
She studied English carefully.
这些动词都是行为动词（或叫实意动词）,具有实际意义的动词.这类动词直接用过去式构成一般过去时.
如果动词是联系动词be时,表“是”,那就用be的过去式was,were.
我们（是)快乐的.-We were happy.
我是男生.-I was a boy.