主格：I，he, she, it, you, they 1.I am a teacher. 2.He is a teacher. 3.You a...

Be 动词的否定 在is , am , are , was , were 后面加not. 缩略式isn't , am not , aren't ...

Be 动词的形式 be , is , am , are , was , were , being , been is , am , are : ...

五种基本句式 （主语：问的是什么 || 谓语：表示动作 || 宾语：主体执行的动作 || 系： || 连接作用的动词 || 表语： 描叙主语性...