各类引导词的区别

★1what交好that 的区别
what在从句中做主语、表语或宾语that在从句中不做成份,只起连接作用(一般在从句中不缺少主语、表语或宾语时用),如:
① What we need is time.
我们所需要的是时间。(主语从句,what做宾语,不可以省略)
② What is needed is time.
所需要的是时间。(主语从句,what这个季节去哪里旅游最好做主语,不可以省略)
③ That he failed in the test again really puzzled us.
他又一次没通过考试让我们迷惑不解。(主语从句,that不做成份,不可以省略)
④ I don’t know that he was seriously ill.
我不知道他病得很严重。(宾语从句,that不做成份,可以省略)
注意对比以下句子
What he said is wrong.
他说的是错的。
That he said so is wrong.
他这么说是错的。
两个句子都是主语从句,第一个句子中whatsaid的宾语;第二个句子中sosaid的宾语,that不做成份,不可以省略)。
手掌发黄另外,有时句子不缺成份时要用连接副词,使句子意思更加完整,如:
The problem is how/where/when /whether we can get more money.
★2whetherif 的区别
1)、在表语从句和同位语从句中只能用whether 不能用if ;当主语从句放于句首时,也只能用whether 不能用if,当it 作形式主语,主语从句放在句末时用whether if均可;discuss后接whether if引导的宾语从句时,必须用whether。如:
Whether you can come will make a difference.
你能否来会不一样。
The question is whether he will be at present at the meeting.
问题是他能否出席会议。
I have no idea whether he will come to our help.
我不知道他是否会帮助我们。
池上碧苔三四点2)、介词的宾语从句用whether不用if ,动词的宾语从句两者均可使用,如:
It depends on whether you can afford the time.
这取决于你是否有时间。
I wonder if/ whether you would like to join us in the outing this weekend.
我想知道这个周末你能否加入我们的郊游。
3)、Whether.. or not whether to do结构中均不用if,如:
Whether the singer can come or not is unknown yet.
那个歌手是否能来不知道。
3 关于连接词的省略问题
在名词性从句中,连接代词和连接副词一般都不省略。只有在宾语从句中,当引导
词是that且充当动词的宾语时可以省略,如:
She told us (that) she would go abroad for further study next year.
她告诉我们她明年要到国外留学。
但是当有两个以上的that引导的宾语从句时,第二个that不省略,如:
He said (that)he felt tired and that he would rather retire .
他说他觉得很累,还说他宁愿退休。
4whowhoever等的区别
1)、who, which在名词性从句中含疑问表示不知是谁,不知哪一个,如:
Who will be invited to the ceremony has not been decided.
邀请谁参加仪式还没定下来。
I am not sure which way I should take.
我不知道走哪条路。
2)、whoever (谓语用单数) =anyone who (whether是什么意思谓语用单数) = those who (谓语用复数 )
Give the dictionary to whoever needs it most.
把字典给最需要的人。(whoever 做主语,此处不能用whomever)
5、从句要使用陈述句语序,如:
Can you tell me where the nearest subway station is?
你能否告诉我最近的地铁站在哪里?
Who can tell me how I can get the post office ?
谁能告诉我怎样才能到达邮局?
Do you know when he will come back?
轻轻的拼音 你知道他什么时候回来吗?
★6、当主句和从句的主语相同时,可以使用连接词+to do ”结构,如:
I wondered what to do next.= what I should do next.
We are not sure when to set out. = when we will set out.