题目内容：

小学英语基本性质,如；BE动词有哪些,BE动词的作用等.要全,

优质解答

现在时 I am, you are, he is, we are, you are, they are （缩略式 I'm, you're, he's, we're, you're, they're）, （否定缩略式 I'm not, isn't, aren't）, 过去时 I was, you were, he was, we were, you were, t...