Must we clean the classroom now?No,you needn't.It ______ after school.A.may clean B.must clean C.need be cleaned D.can be cleaned[正确答案是D,为什么不选C]

分类: 作业答案 • 2021-12-19 11:52:00

问题描述：

Must we clean the classroom now?No,you needn't.It ______ after school.
A.may clean B.must clean C.need be cleaned D.can be cleaned
[正确答案是D,为什么不选C]

答

need 做情态动词时用于否定句和疑问句
做肯定句时用need to do
C如果改成 need cleaning 或need to be cleaned