1. 引导词 what 与 that 的区别
引导主、宾、表语从句时,what 要充当主语、宾语或表语等句子成分,that 不作任何成分,而只在语法上起连接作用。例如:
_________ we can’t get seems better than _________ we have.
A. What; what B. What; that
C. That; that D. That; what
解析:本句包含一个主语从句和一个宾语从句,且两个从句都缺乏宾语,可见两个引导词都必须充当从句的宾语,所以答案为 A 项。
在下面的例句中,that 不充当任何成分,只起语法连接作用(因为句子本身不缺成分):
That the former Iraq president Saddam was captured has been proved.
2. 引导词 whether 和 if 的区别
通常,引导主语从句、表语从句和同位语从句时,连词要用 whether,而不用 if ;习惯上也只能说 whether or not,而不说 if or not .例如:
_________ the meeting will be held in Beijing is not known yet.
A. Whenever B. If C. Whether D. That
解析:题中的从句位于句首,不难知道这是一个主语从句,根据句意,答案为 C 项。但如果宾语或主语从句为否定句时,只能用 that,不能用 whether 引导。如:
That you don’t like him is none of my business.
3. 名词性从句的语序
与别的从句一样,名词性从句必须用自然语序,即使在疑问句中,从句也不倒装(而在主句上倒装)。例如:
No one can be sure _________ in a million years.
A. what man will look like B. what will man look like
C. man will look like what D. what look will man like
解析:由于从句不能倒装,所以答案只能选 A 项。同时还须注意,从句的引导词必须始终置于句首。
4. who / whoever,what / whatever 等的区别
一般说来,what / who 等含特指意义,而 whatever,whoever 等含泛指意义。例如:
It is generally considered unwise to give a child _________ he or she wants.
A. however B. whatever C. whichever D. whenever
解析:答案为 B 项。 Whatever 引导一个宾语从句,并且作 wants 的宾语。这里的 whatever 不能改成 what,因为题意想表达的显然是“无论孩子要什么,就给他 / 她什么是不明智的”,具有泛指的概念。同时要注意,这里 whatever 也不能改用 no matter what,因为后者只能引导状语从句。
5. where,when,why 等连接副词引导的名词性从句
where,when,why 等连接副词也可以引导名词性从句,使用的关键是:这个词必须符合句子的逻辑要求。例如:
— I drove to Zhuhai for the air show last week.
— Is that _________ you had a few days off?
A. why B. when C. that D. where
解析:答案为 A 项,why 引导的从句作表语,同时 why 在从句中作原因状语。又如:
— Do you remember _________ he came?
— Yes. I do,he came by car.
A. how B. when C. that D. if
解析:答案为 A 项。从答语 he came by car 可知,这里问的是 he 来的方式,所以用 how 引导。
6. “介词 + who(m) ”引导的宾语从句与“介词 +who(m) ”引导的宾语从句的区别
介词后面的引导词用主格还是宾语,决定于它在宾语从句中作主语还是宾语。例如:
It was a matter of _________ would take the position.
A. who B. whoever C. whom D. whomever
解析:答案为 A 项。由于这里的引导词在从句中作主语,所以要用主格 who (作宾语时自然要用 whom )。比较下例:
Our country has thousands of excellent scientists,most of whom have received higher education at home.
这是一个“介词 + 关系代词”引导的定语从句。引导定语从句的是“ most of + 关系代词”,而不只是这个关系代词,同时这个引导词又作介词 of 的宾语,所以要用宾格 whom 。
7. 名词性从句中有插入成分时
此时应注意两点:一是从句仍然不倒装,而在插入成分上倒装;二是要注意主语的主格和宾格的选择。例如:
_________ you have seen both fighters,_________ will win?
A. Since; do you think who B. As; who you think
C. When; whoever D. Since; who do you think
解析:答案为 D 项。其中 do you think 是插入成分,其余部分是宾语从句,作 think 的宾语。由于引导词在从句中作主语,所以要用主格 who .
8. 引导词 that 的省略
引导宾语从句时,that 通常可以省略,但引导主语、表语和同位语从句时,that 不能省略。例如:
China’s success in manned-space-craft travel shows _________ out country has become one of the greatest powers in space research.
A. what B. which C. 不填 D. it that
解析:该句中的从句作 shows 的宾语,是宾语从句,又因为从句中不缺主语、宾语,所以只能用 that 引导;又因引导宾语从句时 that 可以省略,所以答案是 C 项。
9. 同位语从句引导词 where,when 的用法特点
说明先行词内容的同位语从句的引导词 where,when 与被说明的名词在概念上不一致。但引导定语从句的引导词却必须保持一致。试比较:
① Then arose the question _________ we were to get so much money.
② This is the house _________ the great man Mao Zedong was born 110 years ago.
A. where B. that C. about which D. in which
解析:①的答案为 A 项;②的答案为 A 项或 D 项。先行词与 where,when 概念一致时,是定语从句,此时,关系副词 where 或 when 可以用“介词 +which ”形式代替。①中的 question 与 where 不表同一概念,可见是同位语从句,where 不能改用“介词 +which ”的形式。②中的 house 与 where 同表地点,所以选 A 项或 D 项都可以。