1.That John won a gold medal is a fact.
It is a fact that John won a gold medal. 2. That I missed the beginning of the film is a pity.
It is a pity that I missed the beginning of the film . 3. That we will go travelling is good news. It is good news that we will go travelling.
形式主语
真正主语
第一种：
形式主语It代替that 主语从句
1. It is + 名词 + that 从句 It is a pity that… It is a shame that …
It is a fact that …. It is an honor that…. 等等
形式主语It代替that 主语从句
主语
seems
possible.动词 That Tom will win the tennis game
seems
表语
possible.
主句
• 主语从句： 在主句中担当主语的是一个从句，这 个从句就叫主语从句。 • 引导词： 从属连词：that, whether • 关系代词：who, whom, what • which, whose • 关系副词：when, where, why
例句 Whom did the boy help? She is an old woman.
Whom the boy helped is an old woman.
Where does he live? It is Beijing. Where he lives is Beijing.
关系代词：
what which who whom等引导主语从句
It + be + 过去分词 + that…
4. That it will rain tomorrow is believed It is believed that it will rain tomorrow. 5.That the waiter works hard is thought. It is thought that the waiter works hard. 6. That the American president will visit China is reported. It is reported that the American President will visit China.
由that引导主语从句
例句： 把两句话合并成一句话 1. Light travels in straight lines. It is known to all.
That light travels in straight lines is known to all.
2. We should wash our hands before meals. It is necessary.
It is reported that ten persons died in the accident.
3. That the earth was not round was believed in ancient times. It was believed in ancient times that the earth was not round.
is necessary. 4. Students say hello to their teachers. It is polite.
That students say hello to their teachers.
is polite.
由that引导主语从句
• 把两句话合并成一句话 5. Your mother didn’t attend the party yesterday. It is a pity.
第四种:形式主语It代替that 主语从句 • It + be + 过去分词 + that…
• It is said that … 据说…..
• It is reported that
据报道…
众所周知….
• It is known to all that …. • It is believed that …. • It is thought that ….
把两句话合并成一句话 1.What do their parents need? It is more experience. What their parents need is more experience.
2.Which doctors will be sent to Wenchuan? It has not been decided. Which doctors will be sent to Wenchuan hasn’t been decided.
It is right that light travels in straight lines. That he got a gold medal is real. It is real that he got a gold medal.
把下列句子用it 做形式主语
1. That Tom will win the game is possible.
名词性从句（一 ）
名 词 性 从 句
主 语 从 句
宾 语 从 句
同 位 语 从 句
表 语 从 句
主语从句
• 把两句话合并成一句话 1. Tom will win the tennis game. It seems impossible.
That Tom will win the tennis game
It is necessary that we must complete this work before 5 o’clcok.
第三种：形式主语It代替that 主语从句
It +不及物动词 +that …
1) That I met my Geography teacher in the street happened. It happened that I met my Geography teacher in the street .
由that引导主语从句
• 把两句话合并成一句话
7. There will be rainy tomorrow. It is possible. That there will be rainy tomorrow is possible.
8.Teenagers smoke. It is wrong. That teenagers smoke is wrong.
由 whether （“是否”）引导的主语从句
• 在主语从句中只能用 此意义时不能用
whether （是否），
if 替换。
形式主语It代替that 主语从句
That we study English well is necessary.
It
is necessary that we study English well.
人们相信… 人们认为….
It + be + 过去分词 + that…
1. That his father has gone to Tianjin is said. It is said that his father has gone to Tianjin. 2. That ten persons died in the accident is reported.
2) That I picked a red wallet on the way to school happened.
It happened that I picked a red wallet on the way to school. 3) That the manager and the boss went travelling happened. It happened that the manager and the boss went travelling.
It is possible that Tom will win the game. 2. That we should wash our hands before meals is necessary. It is necessary that we should wash our hands before meals. 3. That we must complete this work before 5 o’clcock is necessary.
第二种：形式主语It代替that 主语从句
It is + 形容词+ that…
• It is important that…
• It is necessary that…
• It is polite that…. • It is wrong that…等等
把两句话合并成一句话
例句 That light travels in straight lines is right
由 whether （“是否”）引导的主语从句
1. Will he go abroad? It is not known.
Whether he will go abroad is not known.
2. Will it rain tomorrow? It is not known.