肯定句:am/is/are + being + 现在分词
否定句:am/is/are + not + being + 现在分词
一般疑问句:am/is/are + 主语 + being + 现在分词
be动词做谓语通常不用于进行时
强调临时行为或状态(非永久属性)
或构成被动语态
She is a student. 她是一名学生。
She is being a good student. 她此刻表现得像个好学生。
The room is clean. 房间是干净的。
The room is being cleaned. 房间正在被打扫。
(被动语态的现在进行时结构式:am/is/are + being+过去分词。