零基礎學英語：變被動必加to的語法情境

一、使役動詞+賓語

在let, make, have等使役動詞接賓語的結構中，通常用不帶to的不定式。但當使役動詞為被動態(tài)時，不帶to不定式轉為帶to不定式。

主動：Let’s go and play basketball. 讓我們去打籃球吧!

The teacher made him stay there quietly. 老師讓他安靜地呆在那里。

Her father had her do everything. 她爸爸讓她做所有事。

被動：He was made to stay there quietly. 人家讓他安靜地呆在那里。

She was let to tell everything. 她被迫說出一切。

二、感官動詞+賓語

在see, hear, observe, notice, feel, watch等感官動詞接賓語的結構中，用不帶to不定式。但是當以上動詞為被動態(tài)時，不帶to不定式轉為帶to不定式。

主動：I could only see him go. 我只能看著他走。

Mother watched him eat his breakfast. 媽媽看著他吃完早飯。

We felt the house shake. 我們感到房子的震動。

被動：He was seen to enter the house. 有人看到他進入這個房子。

Someone was heard to open the door by us. 我們聽到有人開門。

三、have known+賓語

“have known+賓語” 后用不帶to的不定式，意思是“看過、聽過”，等于“have seen”或“have heard”。同樣，若是被動態(tài)，也需要加to。

主動：We have never known the boy smile.我們從來不知道那個男孩會笑。

被動：That boy has never been known to smile. 沒有人見過那個男孩笑。

不定式有to還是沒有to?什么時候帶to?什么時候不帶to?什么時候既可以帶to又可以不帶to?這些你都get到了嗎?