Mary was heard ___ just now.A laugh B to laugh 为什么选B?不是感官动词后面省略to吗?

Mary was heard ___ just now.A laugh B to laugh 为什么选B?不是感官动词后面省略to吗?
Mary was heard ___ just now.A laugh B to laugh 为什么选B?不是感官动词后面省略to吗?

Mary was heard ___ just now.A laugh B to laugh 为什么选B?不是感官动词后面省略to吗?
这种变为被动句后加上to的情况一般出现在make等词身上……像是She was made to work all day.
用作感官动词时,如果是do sth要加to,如果是doing sth就不加.
但是这种事只出现在被动句中^_^

是选择B
感官动词的确是省略to，但这是主动语态才是省略的
而在被动语态中，则要加上to ，因为句子中was heard是被动语态