如题所述
1. 关于if与whether:两者都可引导宾语从句,常可换用; 但若引导主语从句,则用whether (不用if)。
2. 关于whether和that:两者都可引导主语从句,其区别主要应从句意来考虑:whether表示“是否”,由它引导的主语从句的意思通常是不确定的;that 引导主语从句时,本身没有词义(that在其他名词性从句中也没有词义),但是由that引导的整个主语从句的意思通常是确定的。
2. 关于whether和that:两者都可引导主语从句,其区别主要应从句意来考虑:whether表示“是否”,由它引导的主语从句的意思通常是不确定的;that 引导主语从句时,本身没有词义(that在其他名词性从句中也没有词义),但是由that引导的整个主语从句的意思通常是确定的。
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第1个回答 2016-12-30
引导词that在句中只充当连接词(引导词)成分,只是起语法作用,没有实际的意思。
例:That we became friends is just the fate. 我们成为朋友是命运安排的。
He says (that) he likes playing basketball. 他说他喜欢打篮球。
引导词that做代词,做从句中的代词成分,代替先行词。
例:This is exactly the book that/which accompanied my bedtime in my childhood. 这正是那本陪伴我童年的那本枕边的书。
He is the man (who/that) I mentioned. 他就是我提起过的那个人。
whether做引导词时,它除了做引导词外,还有具体的意思,表示“是否”。
例:Whether he finally signed his name is still a mistery. 他最终是否签了名仍是一个迷。
I strongly doubted whether he stole it. 我强烈怀疑是否是他偷的。
第2个回答 2016-12-30
whether和if的用法区别
whether与if作“是否”讲,在用法上有相同之处,也有不同之处。
一、相同之处。
1.whether和if都能引导宾语从句,常置于see,ask,learn,tell,wonder,doubt,find out等动词之后。
如:He asked me whether/is I could help him. I want to know whether/if he lives there.
2.whether和if都可用it作形式主语从句中。如: it's uncertain whether/if he'll come this evening.
3.在be uncertain/doubtful之后,常用whether引导宾语从句,有时也可以用if,如: We are uncertain whether/if Mary will come.
二、不同之处。
1.whether可置于句首引导主语从句,而if不能。如: ___the 2000 Olympic Games will be in Beijing is not known yet. A.whether B.If C.Whether D.That 答案是C。
2.whether可用在介词之后,引导宾语从句,而If则不能。如: Success depends on whether we make evough effort.
3.whether可引导表语从句,if则不能。如: The puestion is whether it is not worthdoing.
4.在名词之后引导同位语从句时,用whether而不用if。如: The puestion whether the students answered correctly should be decided by the teacher.
5.whether后可接不定式,而if不能。如: Please tell us whether to go or stay here.
6.在有些动词(如discuss)之后,只能用whether,而不用if引导宾语从句。如: We discussed whether we should close the shop.
7.在引导否定概念in宾语从句时,只能用if,而不用whether.如:he asked me if I hadn't finished my work.
参考资料:
whether与if作“是否”讲,在用法上有相同之处,也有不同之处。
一、相同之处。
1.whether和if都能引导宾语从句,常置于see,ask,learn,tell,wonder,doubt,find out等动词之后。
如:He asked me whether/is I could help him. I want to know whether/if he lives there.
2.whether和if都可用it作形式主语从句中。如: it's uncertain whether/if he'll come this evening.
3.在be uncertain/doubtful之后,常用whether引导宾语从句,有时也可以用if,如: We are uncertain whether/if Mary will come.
二、不同之处。
1.whether可置于句首引导主语从句,而if不能。如: ___the 2000 Olympic Games will be in Beijing is not known yet. A.whether B.If C.Whether D.That 答案是C。
2.whether可用在介词之后,引导宾语从句,而If则不能。如: Success depends on whether we make evough effort.
3.whether可引导表语从句,if则不能。如: The puestion is whether it is not worthdoing.
4.在名词之后引导同位语从句时,用whether而不用if。如: The puestion whether the students answered correctly should be decided by the teacher.
5.whether后可接不定式,而if不能。如: Please tell us whether to go or stay here.
6.在有些动词(如discuss)之后,只能用whether,而不用if引导宾语从句。如: We discussed whether we should close the shop.
7.在引导否定概念in宾语从句时,只能用if,而不用whether.如:he asked me if I hadn't finished my work.
参考资料: