if或whether引导宾语从句
一、if或whether引导宾语从句时,作“是否”讲,常放在ask,see,say,know和find out等动词(组)后面。一样情形下,两者常可换用,在口语中多用if。例如
Nobody knows whether (if) it will rain tomorrow. 没有人明白改日是否下雨。
Lucy asked whether (if) they had a cotton sweater. 露西问他们是否有棉制的运动衫
二、if或whether引导宾语从句时,要注意三个方面,即连词、语序和时态。
(1) if或whether不能和that 或其他连词(副词)同时使用,也不能省略。例如:
【译】 我不明白他今天是否会来。
【误】 I don't know that if (whether) he will come here today.
【正】 I don't know if (whether) he will come here today.
(2) if或whether引导宾语从句时,但从句应用陈述句语序。例如:
“Do you know the way to the hospital?” the old woman asked me. (合并为宾语从句)
The old woman asked me if (whether) I knew the way to the hospital. 老妇人问我是否明白去医院的路。
(3) if或whether引导的宾语从句的时态应和主句保持一致。即主句为一样现在时或一样今后时,从句可依照需要选用任一种时态;主句为一样过去时,从句则用过去时中的任一种时态。例如:
I don't know if (whether) he has come here. 我不明白他是否来过这儿。
三、if和whether的区别
(1) 在动词不定式之前只能用whether 。例如:
I can't decide whether to stay.我不能决定是否留下。
whether是什么意思(2) whether后可直截了当接or not,而if不能够。例如:
I want to know whether or not it's good news. 我想明白是否是好消息。
(3) 在介词后,只能用whether。例如:
His father is worried about whether he will lose his work. 他的父亲担忧是否会失去工作。
(4) 宾语从句放在句首表示强调时,只能用whether。例如:
Whether they can finish the work on time is still a problem. 他们是否能准时完成这项工作依旧个问题。
(5) 用if会引起歧义时,只用whether。例如:
Could you tell me if you know the answer?
这句话有两种意思:“你能告诉我是否明白答案吗?”或“假如你明白答案,请告诉我,好吗?”。如用whether可幸免歧义。
(6) 假如主句已有一个if引导的条件句,为了幸免产生混淆,应使用whether。例如:
He asked me whether, if there was enough time, I wanted to go to his office. 他问我如有足够的时刻是否想去他的办公室。
(7) whether可引导主语从句,if则不能。例如:
Whether you can stay with my mother is another matter. 你是否能与我母亲呆在一起是另一回事。
(8) whether可引导表语从句,if则不能。例如:
The question is whether this material can be used in our factory. 问题是我们工厂能否使用这种材料。
【巩固精练】
翻译下列句子。
1. 他走过来看他的猫是否出了问题。
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2. 汤姆问我是否看过这本书。
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3. 妈妈问爸爸假如来了许多客人,我们是否去饭店吃晚饭。
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4. 她妹妹是否能参加聚会依旧个隐秘。
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参考答案:
1. He came to see if (whether) there was something wrong with his cat.
2. Tom asked me if (whether) I had read the book.
3. Mom asked Dad whether we would have dinner in a restaurant if there were too many guests.
4. Whether her sister will come to the party is still a secret.