被動語態(tài)還原to的口訣：一感二聽三讓四看半幫助。這些詞包括feel，hear，listen to，make，have，let，see，watch，look at，observe，notice，help等。

被動語態(tài)中to的還原

不帶to的動詞不定式作賓語補(bǔ)足語的主動語態(tài)改為被動語態(tài)時，省略的to要加上。

?？嫉膭釉~有make，let，have，see，watch，notice，hear等。

例如：

1.They heard the children sing that morning.

→The children were heard to sing that morning.

2.The teacher made the little boy stand in the classroom.

→The little was made to stand in the classroom by the teacher.

3.We saw them play football just now.

→They were seen to play football just now.

4.We often hear her sing in English.

→She is often heard to sing in English.

一感二聽三讓四看半幫助

一感:feel

二聽:hear，listen to

三讓:make，have，let

五看:see，watch，look at，observe，notice

半幫助:help(指其后的不定式可帶可不帶to)

這些動詞后,如跟不定式作賓補(bǔ),則在主動語態(tài)中，不定式不帶to,但在被動語態(tài)中要帶to,如:

He felt something move beside him...

他感覺身邊有什么東西在動.

I heard the girl sing an English song.

He often makes his sister cry.

His sister is often made to cry.

Have you seen a young man pass by

Mother watched her son play in the park.

Can you help me (to) carry the box?

Let me have a try.

Please listen to the man tell the story.