一.主語從句
主語從句是在復(fù)合句中充當(dāng)主語的從句,通常放在主句謂語動詞之前或由形式主語it代替,而本身放在句子末尾。
1. It 作形式主語和it引導(dǎo)強(qiáng)調(diào)句的比較
It 作形式主語代替主語從句,主要是為了平衡句子結(jié)構(gòu),主語從句的連接詞沒有變化。而it引導(dǎo)的強(qiáng)調(diào)句則是對句子某一部分進(jìn)行強(qiáng)調(diào),無論強(qiáng)調(diào)的是什么成分,都可用連詞that。被強(qiáng)調(diào)部分指人是也可用who/whom。例如:
It is a pity that you didn’t go to see the film.
It doesn’t interest me whether you succeed or not.
It is in the morning that the murder took place.
It is John that broke the window.
2. 用it 作形式主語的結(jié)構(gòu)
(1) It is +名詞+從句
It is a fact that … 事實是…
It is an honor that …非常榮幸
It is common knowledge that …是常識
(2) it is +形容詞+從句
It is natural that… 很自然…
It is strange that… 奇怪的是…
(3) it is +不及物動詞+從句
It seems that… 似乎…
It happened that… 碰巧…