He is often heard _____ in the next room.A.singing B.sang C.to singing D.to sing 为什么答案是A而不时D呢?hear sb do sth变成被动语态后,do sth前面不是要加上to

分类: 作业答案 • 2022-02-17 11:54:24

问题描述：

He is often heard _____ in the next room.
A.singing B.sang C.to singing D.to sing
为什么答案是A而不时D呢?
hear sb do sth变成被动语态后,do sth前面不是要加上to

答