大學(xué)英語四級語法大全目錄

祈使句用以表達命令，要求，請求，勸告等。

1) 祈使句有兩種類型，一種是以動詞原形開頭，在動詞原形之前加do (但只限于省略第二人稱主語的句子)。

Take this seat.

Do be careful.

否定結(jié)構(gòu)：

Don't move.

Don't be late.

2) 第二種祈使句以let開頭。

Let 的反意疑問句

a. Let's 包括說話者

Let's have another try，shall we / shan't we?

= Shall we have another try?

b. Let us 不包括說話者

Let us have another try，will you / won't you?

= Will you please let us have another try?

否定結(jié)構(gòu)：

Let's not talk of that matter.

Let us not talk of that matter.