北木教育 > 托福 > 托福文章 > TOEFL实用语法系列——如何理解长难句之表语从句
发布时间:2018-09-12 北京智赢
定义:在一个复合句中,从句充当的是主句的表语成分;是名词性从句的一种。其实也可以把它理解为主句谓语是系动词(be, become, appear, seem, look, sound, feel, get, smell等词)的宾语从句。所以表语从句的用法跟宾语从句几乎一致。
如"Theproblem is when we can get a pay rise. "——问题是什么时候我们可以涨工资。"The problem"是主句主语,"is"是系动词,充当主句的谓语动词,"when we can get a pay rise"就是表语从句,解释说明“问题”的内容。
引导表语从句的连词主要有:(表语从句的连词不能省略)
that,what, who, when, where, which, why, whether, how, whoever,whichever ,whatever
because,as if, as though
表语从句的用法及时态
1.用法
表语从句的语序要用陈述句语序,如:
Hissuggestion is that we should stay calm.
Thequestion is when he can arrive at the hotel.
注意:表语从句只能置于主句之后,而主句的谓语动词只能是系动词。
2.时态(所有名词性从句的时态都遵从以下规则):
(1)主句谓语动词是现在时(一般现在时、现在进行时、现在完成时等)或将来时(一般将来时、将来进行时),从句谓语动词可以用任何所需的时态。
Thatis what I want to tell you.
Thatis why he cried yesterday.
(2)主句谓语动词是过去时(一般过去时、过去将来时等),从句谓语动词一般可用过去时(一般过去时、过去进行时、过去完成时、过去将来时)。
What Itold him was that I would find him a good play.
What Ifelt was that he was sick last week.
(3)客观的条件,从句时态不受影响。
It wasbecause the sky is blue.
表语从句跟宾语从句的区别
1.表语从句的连词不能省略;
2.表语从句只能置于主句之后,而主句的谓语动词只能是系动词;
3.if/whether(表是否时)引导名词性从句时的用法辨析:
if不能引导表语从句,只能用whether 来引导;
False:The question is if the enemy is marching towards us.
Right:The question is whether the enemy is marching towards us.
提示:引导宾语从句时if/whether有时可以互换,所以在考试中要表达“是否”这个意思时,都用“whether”,避免不必要的错误。