3. 當(dāng)從句是由選擇問句轉(zhuǎn)化而成時，一定要用whether構(gòu)成whether...or結(jié)構(gòu)。

2. 主句和從句要保持時態(tài)上的一致性，從句還要保持陳述句語序。

1. 由從屬連詞that引導(dǎo)的從句叫做名詞性that-從句。 That只起連接主句和從句的作用，在從句中不擔(dān)任任何成分，本身也沒有詞義。名詞性that-從句在句中能充當(dāng)主語、賓語、表語、同位語

同位語從句中先行詞不充當(dāng)從句成分，從句是用來解釋先行詞的內(nèi)容。That從句作同位語，that不能省略。

▲Word came that our football team had won the match. 消息傳來，我們的足球隊贏了比賽。

▲May I ask a question when the meeting will be held? 我能否問個問題，會議什么時候舉行？

第二節(jié) 實戰(zhàn)演練

賓語從句在句中作賓語，引導(dǎo)賓語從句的that可以省略。whether和if可互換，但介詞賓語或有or not時，用whether.

▲They know that the habit may kill them. 他們知道這個習(xí)慣能使他們致死。

▲They doubt whether or not Jack is a good student. 他們懷疑Jack是否是一個好學(xué)生。

▲They wanted to see which shops offered the best advice and service. 他們想了解哪家店提出的建議和提供的服務(wù)最好。

表語從句在句中作表語，它位于主句的聯(lián)系動詞之后。that從句作表語，that不能省略。表語從句只用whether，不用if。

▲The problem is that smokers cannot go without smoking. 問題是抽煙的人不抽煙就會感到難受。

▲The question is whether it is worth doing. 問題是這是否值得做。

▲This is where he has worked for years. 這就是他多年工作的地方。

3. It作形式主語主要包括以下幾種類型和搭配關(guān)系：

　 1)It + be + adj. + 從句 　　　　 It was obvious that the driver could not control his car. 　　　 2)It + be + n. + 從句 　　　　 It is a pity that he missed the lecture.

　 3)It + be + 過去分詞 + 從句 　　　　 It is said that they have won the game.

　 4)It + be + vi. + 從句

　　 It seems that something is wrong with the computer.

2. 很多主語從句都可以用that作形式主語。例如：

It is very interesting that he likes such kind of books.

It remains a question whether he will be able to come.

1. 用作主語的從句叫主語從句。that從句作主語，that不能省略。

▲That he likes such kind of books is very interesting.他喜歡這種書是非常有趣的。 　　 ▲Whether he will be able to come remains a question. 他是否能夠來仍然是一個問題。

▲What he is looking for is none of your business. 他在找什么與你無關(guān)。

2. 名詞性wh-從句，即以wh-詞連接的名詞性從句。Wh-詞包括：

　 連接代詞：who, whom, whose, what, which, whoever, whatever, whichever

　 連接副詞：when, where, how, why

連接詞whether, if不充當(dāng)句子的任何成分。