神马作文网if和 whether的区别
来源：学生作业帮 编辑：神马作文网作业帮 分类：英语作业 时间：2024/11/19 11:28:03
if和 whether的区别
什么时候不能用if
什么时候不能用if
一般的疑问句都用if来表示是否
但是有下面几个情况 只能用whether
1 引导主语从句的时候
2 在介词后面的时候
3 后面跟不定式的时候
4 句末有显示选择性的词语 尤其是“or not”的出现
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.
但是有下面几个情况 只能用whether
1 引导主语从句的时候
2 在介词后面的时候
3 后面跟不定式的时候
4 句末有显示选择性的词语 尤其是“or not”的出现
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.