名词性从句专题(含答案)

名词性从句专题(含答案)

一、名词性从句

1．Exactly _________ the potato was introduced into Europe is uncertain, but it was probably around 1565.

A. whether

B. when

C. why

D. how

【答案】 B

【解析】【分析】句意：土豆被引进欧洲具体的事件不被确定，但是可能是在1565年左右。根据时间状语round 1565得知这里是指时间不确定。故选B。

【点评】考查名词性从句，本题涉及when引导的主语从句。

2． is clear to the members of the committee is that the President will not give in to their demands.

A. Who

B. It

C. As

D. What

【答案】 D

【解析】【分析】句意：委员会成员清楚的是，总统不会向他们的要求让步。that the President will not give in to their demands.这个句子作表语； is clear to the members of the committee这是主语从句，这里缺少主语从句的连接词，并且连接词在句中作主语，it是代词，不是了；连接词，故排除B；as作主语时，是在定语从句中，故排除C；who指人，根据表语指的事情，不是人，故排除A；what在主语从句中可以作主语或宾语，指事，符合句意，故选D。

【点评】考查名词性从句，本题涉及what引导的主语从句。

3．________ is known to us all that the old scientist, for ________ life was hard in the past, still works hard in his eighties.

A. As; whose

B. It; whose

C. As; whom

D. It; whom

【答案】 D

【解析】【分析】句意：我们都知道，那位老科学家，过去生活很艰苦，到了八十多岁还在努力工作。第一空it is known t o us all that…是个固定句型，意为“众所周知…”；第二空为介词+关系代词引导的定语从句，先行词the old scientist指人，作介词for的宾语，只能用whom，故选D。

【点评】考查名词性从句和定语从句，本题涉及固定句式it is known to us all that…和whom引导的限制性定语从句。

4． is even more important is the earth cooled down, water began to appear on its surface.

A. When; that; when

B. What; whether; as

C. What; that; as

D. lt; whether; as

【答案】 C

【解析】【分析】这题考查从句的用法，第一空填what引导主语从句，在主语从句中what做主语，第二空填that引导表语从句，在表语从句中，as是引导时间状语从句，句意是：甚至更重要的是：随着地球的冷却，水开始出现在表面。选C。

5．_______ are playing an important part is well known to us all.

A. That who

B. Those who

C. Who that

D. Who

【答案】 D

【解析】【分析】考查主语从句。句意：谁起着重要作用，这是众所周知的。主语从句缺少引导词，从句缺少主语，故选D。

6．Has it been announced ______?

A. when are the planes to take off

B. that are the planes to take off

C. where are the planes to take off

D. when the planes are to take off

【答案】 D

【解析】【分析】句意: 飞机什么时候起飞已经宣布了吗？此处是when引导的主语从句，且要用陈述句语序，故选D。

【点评】考查名词性从句，it作形式主语，关系副词when引导的从句作真正的主语。

7．In the past decade, our education system too much on grades. However, grades have a direct connection with future success is still a question.

A. focused; whether

B. focused; if

C. has focused; whether

D. has focused; if

【答案】 C

【解析】【分析】考查时态和主语从句。根据In the past decade,在最近的几十年里，可知句子用现在完成时态，our education system是句子的主语，单数形式，所以第一空填has focused；第二空是主语从句做主语，if是否，不能引导主语从句，所以第二空填whether。故选C。

【点评】主语从句主要有三类：

1）（1）由连词that引导的主语从句:引导词that无含义,在句中不做成分,不可以省。例如：That you will win the medal seems unlikely.你想获得奖牌看起来是不可能的。（2）用连词whether 引导的主语从句:whether有含义（是否）,在句中不做成分,不可以省。例如：Whether she is coming or not doesn't matter too much.她来不来都无关紧要。注意：if不能引导主语从句。

2）用连接代词引导的主语从句（在由连接代词who, whose, whom, which, what, whoever,