楊慶春
一、條件狀語(yǔ)從句句型
條件狀語(yǔ)從句表示主句動(dòng)作發(fā)生的條件, 引導(dǎo)條件狀語(yǔ)從句的連接詞有:if,意為“如果;假設(shè)”;unless,意為“如果不;除非”。if從句可放在主句前或主句后,從句置于主句前時(shí),須用逗號(hào)與主句隔開,反之則不用逗號(hào)。
1. if從句,主語(yǔ)+will(not)+動(dòng)詞原形,在此句型中,從句談?wù)摰氖且粋€(gè)可能發(fā)生事實(shí)的條件,主句表示其產(chǎn)生的相應(yīng)結(jié)果。
If you ask him, he will help you. 如果你請(qǐng)他幫忙,他會(huì)幫助你的。
If it doesn’t rain, we’ll go to the Great Wall. 如果明天不下雨,我們就去長(zhǎng)城。
2. if從句+祈使句,在此句型中,從句表示能夠發(fā)生或可能發(fā)生的事情(如果……),主句表達(dá)建議(就……)。此時(shí),從句謂語(yǔ)動(dòng)詞要用一般現(xiàn)在時(shí)態(tài)。
Please ring me up if you have time this evening. 如果你今晚上有空的話,請(qǐng)給我打電話。
If you want to go, please let me know. 如果你想要去,請(qǐng)讓我知道。
3. if從句,主語(yǔ)+may(can, might, could…)+ 動(dòng)詞原形,在此句型中,從句表示能夠發(fā)生或可能發(fā)生的事情,主句表達(dá)主觀上能夠或者應(yīng)該做什么。
If it stops snowing, we can go out. 如果雪停了,我們就可以出去了。
If you want to lose weight, you should take more exercise. 你要想減肥,就應(yīng)該多運(yùn)動(dòng)。
二、條件句與簡(jiǎn)單句的關(guān)系
句型:祈使句+and (or, then)+簡(jiǎn)單句(用一般將來時(shí)),這種句型相當(dāng)于if引導(dǎo)的一個(gè)條件狀語(yǔ)從句。從意義上可以看出祈使句表示一種條件或假設(shè),陳述句表示一個(gè)結(jié)果。因此這個(gè)句型通??梢赞D(zhuǎn)換成“if條件狀語(yǔ)從句+主句”形式。
1. 祈使句與簡(jiǎn)單句之間常有一個(gè)逗號(hào),如果表示順承關(guān)系,用and連接前后句。and后面的簡(jiǎn)單句中謂語(yǔ)動(dòng)詞常用將來時(shí),主語(yǔ)通常是you,也可用其他人稱。改寫成if條件狀語(yǔ)從句時(shí)要去掉and。
Study hard, and you will pass the exam. 努力學(xué)習(xí),你會(huì)通過考試的。
=If you work hard, you will pass the exam.
2. 如果表示轉(zhuǎn)折關(guān)系則用or。or意為“否則”,表示從反面來預(yù)測(cè)一個(gè)結(jié)果。因此,需要把if條件句變?yōu)榉穸ň湫问剑@樣意思才能完整。
Work hard, or you won’t pass the exam. 你要是不努力學(xué)習(xí),考試就不會(huì)及格。
= Work hard, and you will pass the exam.
= If you work hard, you will pass the exam.
= If you don’t work hard, you won’t pass the exam.
Hurry up, or you’ll be late. =If you don’t hurry up, you’ll be late.
3. 祈使句+ then+ 簡(jiǎn)單句,這種句型中的then不是并列連詞,而是連接副詞,改寫成if條件狀語(yǔ)從句時(shí)要去掉then。
Use you head, then you’ll find a good way. 動(dòng)腦,你會(huì)找到一個(gè)好的方法。
= If you use your head, you’ll find a good way.
Go into the cave, then they won’t see you. 進(jìn)入洞穴,他們不會(huì)看見你的。
= If you go into the cave, they won’t see you.
4. 介詞with或without表示假設(shè)關(guān)系時(shí),可以改寫成if條件狀語(yǔ)從句。
Without water, nothing could live. 沒有水,就沒有生命。
= If there ware no water, nothing could live.
With your help, I’ll certainly be good at physics.
= If I have your help, I’ll certainly be good at physics.
小練習(xí):用if 連接下面的句子。
1. You do not understand the article. Please ask your teacher.
2. You want to know more about it. Please call your teacher.
3. Tell him to make a phone call to me. He will come here tomorrow.
4. You want to go. Please tell me.
5. We will have no water to drink. We don’t protect the earth.
Keys:
1. If you do not understand the article, please ask your teacher.
2. If you want to know more about it, please call your teacher.
3. If he comes here tomorrow, tell him to make a phone call to me.
4. If you want to go, please tell me.
5. If we don’t protect the earth, we will have no water to drink.