Listen！Is Tim heard (   ) in the room now?

A.to sing

B.singing

答案是A，我知道这种还原不定时符号to的用法。我的疑问是既然是让听，那么应该是正在唱歌，用现在分词表示正在 有错么？

感谢老师指点~！

谢谢。

回答如下：

感官动词，主动省略TO 接不定式作宾语补足语，主动加TO

结构如下：

【1】hear sb do sth 听见某人做了某事

She heard someone come in just now.

【2】sb be heard to do sth 某人被听见做了某事

Someone was heard to come in just now.

【3】hear sb doing sth 听见某人正在做某事

We hear Mary singing in the room.

【4】sb be heard doing sth 某人被听见正在做某事

Mary is heard singing in the room.