[语法初识]

原句感知 自主探究 1.Exactly when the first people arrived in what we now know as California, no one really knows.

2．However, it is likely that Native Americans were living in California at least fifteen thousand years ago.

3．Scientists believe that these settlers crossed the Bering Strait in the Arctic to America by means of a land bridge which existed in prehistoric times.

4．That is why today over 40% of Californians speak Spanish as a first or second language.

5．It is believed that before long the mix of nationalities will be so great that there will be no distinct major racial or cultural groups, but simply a mixture of many races and cultures. (1)what在例句1和that在例句3中引导宾语从句。

(2)that 在例句2、5中引导主语从句，that不可省略。例句2、5中it为形式主语。

(3)why在例句4中引导表语从句。 　　

　　[语法剖析]

语法点一 主语从句 　　

　　主语从句是在复合句中充当主语的从句，通常放在主句谓语动词之前或由形式主语it代替，而本身则放在句子末尾。引导主语从句的连词有that, whether, who, what, whatever等。

　　1．that引导的主语从句

　　that在主语从句中不充当任何成分，无任何含义，只起连接作用，但that不能省略。that从句很长时，有时可用it作形式主语。

　　That she passed the exam made us very happy.

　　她通过了考试使得我们非常高兴。

　　That he finished writing the composition in such a short time surprised us all.

　　＝ It surprised us all that he finished writing the composition in such a short time.

　　他能在这样短的时间内写完作文让我们感到吃惊。

　　[常用句型]

　　(1)It be ＋形容词(possible, strange, natural, important, necessary ...)＋that从句

　　It is necessary that people should learn to face the reality.

　　人们应该学会面对现实是有必要的。

　　(2)It be ＋名词短语(a pity, a fact, a wonder, an honour, no wonder ...)＋that从句

　　It is a fact that smoking is a danger to health.

　　吸烟危害健康，这是事实。

　　(3)It ＋不及物动词(seem, occur, happen ...)＋that从句

　　It occurred to me that I would travel to Europe.

　　我突然想到要去欧洲旅行。

(4)It be ＋过去分词(said, thought, believed, supposed, reported ...)＋that从句