(共14张PPT)
主语从句
subjective clause
1. 定义
定义:在主从复合句中,充当主语的从句叫主语从句,它是名词性从句之一。主语从句使用陈述语序,其通常结构为“引导词 + 主语 + 谓语 /系动词+ 其他成分”;但当连接代词同时充当从句主语时,其结构为“连接代词 + 谓语/系动词 + 其他成分”。
What worries many people is that these chemicals may even cause cancer.
主语从句 系 表
令很多人所担心的是,这些化学制品甚至可能导致癌症。
2.引导主语从句的连接词
引导主语从句的连接词有三类:
从属连词(that,whether,if):在从句中不作成分;
连接代词(who,whom,whose,what,which,whoever,whatever,whichever ):在从句中作主语、宾语、表语或定语;
连接副词(when,where,why,how):在从句中作状语;
(1)从属连词:that,whether,if
①that 在从句中不充当句子成分,也无意义,只起连接作用,但不可省略。
That he is still alive is a wonder. 他还活着真是一个奇迹。
②whether 和if在从句中不充当句子成分,只起连接作用,意为“是否”。whether 引导的主语从句既可放在句首,也可放在句中。但由if 引导的主语从句不能放在句首,只能放在句中。
Whether we can go there depends on the weather.
我们能否去那儿取决于天气。
whether和if引导的名词性从句的区别:
用法 whether if
引导位于句中的主语从句 √ √
引导位于句首的主语从句 √ ×
引导表语从句 √ ×
做介词之后的宾语 √ ×
和or not 连用 √ ×
I'm uncertain whether to go or not.
我不确定去还是不去。
We have to talk about whether you can travel alone.
我们得谈谈你能否单独旅行。
(2)连接代词:who,whom,whose,what,which,whoever,whatever,whichever 等。
连接代词引导主语从句时,在句中既起连接作用,又在从句中充当主语、宾语、表语或定语。
Who will bring up the child hasn’t been decided yet.
谁来抚养这个孩子还没有决定下来。(主语)
What you did made him angry.(宾语)
你做的事让他生气。
(3)连接副词:when,where,why,how。
在从句中作状语,分别表示时间、地点、原因和方式。
When we will set off hasn’t been decided.我们何时出发还没有决定。
Why he spied on me puzzled me for a long time.
他为什么监视我这个问题困扰了我很长时间。
How he earned his living before is not clear to us.
我们不清楚他以前是如何谋生的。
单句语法填空
(1)It makes no difference ____________ you support my plan or not.
(2)____________ you do should do no harm to others.
(3)It is suggested ____________ the work(should)be done with great care.
whether
Whatever
that
3.用it 作形式主语的主语从句
当主语从句太长,为了避免头重脚轻,常用it 作形式主语,而把主语从句后置。用it 作形式主语的常见句型有:
(1)It+be+ 形容词 +that 从句.
常用于该句型的形容词有clear,obvious,true,natural,possible,likely,certain,fortunate,strange,necessary,important 等。
It was clear that the girl told a lie. 很明显,那个女孩说谎了。
(2)It+be+ 名词(词组)+that 从句 .
常用于该句型的名词(词组)有a pity,a shame,good news,a fact,an honour,a wonder,no wonder (不足为奇)等。
It is a pity that your parents didn’t permit you to go with us.
你父母不允许你和我们一起去,真遗憾。
(3)It+be+ 过去分词 + that 从句.
常用于该句型的过去分词有said,believed,reported,thought,expected,decided,announced,suggested,hoped 等。
It is reported that a earthquake happened in Japan.
据报道,日本发生了地震。
(4)It + 不及物动词(短语)+ that 从句 .
常用于该句型的不及物动词(短语)有seem(看上去),turn out (证明是),happen(碰巧),appear(显得)等。
It appears that there has been a mistake. 看来有一个错误。
Let’s practice!
专项练习
单句语法填空
(1)[词汇复现]It is certain ____________ the boy is reliable.
(2)It ____________(be) obvious that the driver could not control his car.
(3) Is it possible that they ____________(come)tomorrow
(4)____________ is clear that he is telling the truth.
(5)[词汇复现]It worried her a bit ____________ her mother didn’t approve of her leaving home tonight.
(6)It ____________(shock) me that Peter didn’t tell anybody where he was.
完成句子
(7)____________________(都没有关系)whether he likes it or not.
(8)[词汇复现]______________________(结果是) our assumption was wrong.
that
was
will come
It
that
shocked
It doesn’t matter
It turned out that
THE END