c . It +be +过去分词(said, reported, thought, expected, decided, announced, arranged, agreed, suggested etc.)+that从句。如：

It is said that Mr. Green has arrived in Beijing.

It is reported that China has sent another man-made earth satellite into orbit.

It is suggested that we should carry out the reform in the following years.

d. It + seem, happen等不及物动词及短语+that从句。如：

It seems that Alice is not coming to the party at all.

It happened that I was out that day.

e. It + doesn't matter (makes no difference, etc.)+连接代词或连接副词引起的主语从句。如：

It doesn't matter whether she will come or not.

It makes no difference where we shall have the meeting.

2. that和what的选用

　that和what都可引导主语从句。what除了起连接作用外，还在名词性从句中充当某些成分，可作从句的主语、宾语或表语。而that在名词性从句中不充当任何成分，无词义，只起连接词作用。如：What he wants is a book. That light travels in straight lines is known to all.

四 我的练习 1. 用适当的连接词填空

1) __________ they will talk about the matter won't make too much difference. In fact, it is the attitude not the place that matters.

2) It hit me suddenly __________I had forgotten her birthday.

3) It is still unknown __________ caused the accident last Saturday.

4) __________ wants to stay in a hotel has to pay their own.

5) --- What made her so sad?

--- __________ she failed in the English contest.

2. 完成句子

1). 他是如何设法成功的仍然是个迷。

______________________is still a mystery.

1) ____________________(是否在户外开晚)in the open air tomorrow depends on the weather.