使役動詞后不定式符號to的省略問題

第一種情況：當不定式用于let, make, have等使役動詞后作賓語補足語時，不定式必須省略to。如：

Let me give you a piece of advice. 讓我給你一個忠告。

He had his son clean the car. 他叫他的兒子擦車。

They made me repeat the whole story. 他們非讓我把整個事件再說一遍。

但是，當使役動詞用于被動語態時，其后的不定式則必須要帶to。如：

雖然他以前經常把他小妹妹弄哭，但今天他被他小妹妹弄哭了。

誤：Though he had often made his little sister cry, today he was made cry by his little sister.

正：Though he had often made his little sister cry, today he was made to cry by his little sister.

注意，表示使役意義的let和have很少用于被動語態。

第二種情況：表示“使”“迫使”的force, get, oblige等動詞后接不定式作賓語補足語時，不定式必須帶to（不能省略）。如：

They forced her to sign the paper. 他們強迫她在文件上簽字。

The police obliged him to leave. 警方強迫他離開。

Once she has decided on doing it, you won’t get her to change her mind. 一旦她下決心干，你就別想使她改變主意。