2) It is + adj. +that It’s certain that… 肯定… It is possible/likely that... 很可能…… It is obvious/clear that… 很明显… It is true that…的确…
It is necessary \important \natural\... that…
known.
•主语从句的特点：
1.引导词：
从属连词 that, whether； 连接代词 who, what, which；
whoever, whatever, whichever; 连接副词 when, where, how和why。
2. 语序：陈述句语序
3. 在主语从句中只能用whether,不能用if
• 2.明确it作形式主语和形式宾语、代替主语 从句及宾语从句的用法，及其与强调句的 区别。
• 3.区分that引导的同位语从句及定语从句。
理解主语从句
他通过了考试让老师很高兴。
He passed the exam. It made the teacher happy. He passed the exam made the teacher
• Whether he will come is uncertain.
_t_h_a_t_ 只起引导作用，本身无意义，不充当
任何分，但不能省略。
whether 不做成分，表“__是__否___”。 在主语从句中只能用 _w_h_e__t_h_e_r_,不能用i__f_பைடு நூலகம்
引导词
2) 连接代词who, what, which
*__It__is_a__p_i_ty__th_a_t__(很可惜)we lost the match. *__It__is_a__f_a_ct__th_a_t_(这是事实)he cheated in the exam.
1. 令人吃惊的是他改变了主意。 It is a surprise that he changed his mind.
这样就构成了下面一些常用句型:
1) It is + n. +that
It is a pity/shame that... 可惜的是……
It is a surprise that… 令人吃惊的是…
It is a fact that…
事实是…
It is common knowledge that … …是常识
主语从句 (Subject Clause)
在主从复合句中充当主语的从句就 是主语从句, 它是名词性从句之一。 引导主语从句的连接词有： 从属连词that, whether；连接代词 who, what和which；连接副词 when, where, how和why。
• 1.了解名词性从句的基本用法，掌握名词性 从句的引导词及引导词在名词性从句中的 作用，辨析that与what,if与whether等引导 词的用法。
找出主语从句
That he will succeed is certain. Whether he will come makes no
difference. What we need is more time.
引导词
1) 从属连词that和whether：
• That he will come is certain.
2. 真可惜你错过了这么一个好机会。 It is a pity that you missed such a good
chance. 3. 事实是我们周围的污染正变得越来越严重。
It is a fact that the pollution around us is becoming more and more serious.
• Whatever I have is yours.
• Whichever you want is yours.
whatever=anything that whoever=anyone who
引导词
4) 连接副词when, where, how ,why
• When we will leave hasn’t been decided. • How she keeps healthy is a secret. • Why he cries is not clear. • Where the meeting will be held is not
• Who will go makes no difference. • What we need is more time. • Which book I shall choose hasn’t
been decided.
引导词
3)连接代词whoever, whatever, whichever • Whoever comes is welcome.
什么是主语？
I like English. The train left.
主语：是一个句子说明的人或事物,即叙
述的主题，一般位于_句__首___ 。
找出主语
Jim is good at playing the piano. (名词 To see is to believe. （不定式） ） Smoking is bad for health. （动名词） What he has said is true. (从句）
happy. That he passed the exam made the teacher happy.
理解主语从句
他何时要来还不清楚。 When will he come? It is not clear. When will he come is not clear.
When he will come is not clear.
That he will win the match is certain.
It is certain that he will win the match.
注解：一般来说主语从句都是放在 句首 , 但有时为了使句子 保持平衡 ，避免"头重脚轻", 常用 it 作 形式主语 ，从而把主语从句放在 后面 ．