初中·課本中不會(huì)教你的 574　“祈使句+and+陳述句”和“祈使句+or+陳述句”的區(qū)別

574　“祈使句+and+陳述句”和“祈使句+or+陳述句”的區(qū)別

1　祈使句+and+陳述句 是一種常用句型，這里的祈使句必須是肯定的，表示條件或假設(shè)，相當(dāng)于if引導(dǎo)的肯定從句，and 后的陳述句表示結(jié)果，常用一般將來(lái)時(shí)。

比較

祈使句+and+陳述句

If從句(肯定)+陳述句

Come early, and you will see her. 早些來(lái)，你就會(huì)見到她。

If you come early, you will see her.

Study hard, and you will pass the exam. 努力學(xué)習(xí)，你就會(huì)通過(guò)這次考試。

If you study hard, you will pass the exam.

Think carefully, and you will find the answer. 好好想想，你就會(huì)找到答案。

If you think carefully, you will find the answer.

2　祈使句+or+陳述句 中的or 表示“不然的話，要不然”，祈使句仍表示條件或假設(shè)，相當(dāng)于if引導(dǎo)的否定從句，or 后面的陳述句表示反面的結(jié)果。這種結(jié)構(gòu)的祈使句常用肯定式。

比較

祈使句+or+陳述句（用否定意義的動(dòng)詞）

If從句(否定)+陳述句

祈使句(肯定)+and+陳述句(用肯定意義的動(dòng)詞)

Work hard, or you'll fail the exam. 努力學(xué)習(xí)，不然你就會(huì)考不及格。（fail有否定意義）

If you don't work hard, you'll fail the exam.

Work hard, and you'll pass the exam. （pass有肯定意義）

Get up early, or you'll miss the train. 早點(diǎn)起床，不然你會(huì)誤車的。（miss有否定意義）

If you don't get up early, you'll miss the train.

If you don't get up early, you won't catch the train.

Get up early and you'll catch the train. （catch有肯定意義）

提示

祈使句+or+陳述句結(jié)構(gòu)中的祈使句有時(shí)也可用否定式，這時(shí)，要轉(zhuǎn)換為if從句的肯定式。

不要吃得太多，不然你會(huì)生病的。

Don't eat too much, or you'll get ill.

If you eat too much, you'll get ill.

不要睡在戶外，不然你會(huì)感冒的。

Don't sleep in the open, or you'll catch a cold.

If you sleep in the open, you'll catch a cold.