宾语从句的知识点

用作宾语的从句叫宾语从句.宾语从句不仅可以用作及物动词的宾语,还可以用作介词或某些形容词的宾语.宾语从句的语序只能用作陈述句语序.
一、宾语从句的引导词
1.由连词that引导,在口语或非正式文体中可以省略.例如：
He said he would go to Tokyo on business the next day.
注意：
当引导词that引导几个表示并列关系的宾语从句时,最后一个that不能省掉.
2.由if,whether引导,宾语从句属于一般疑问句时,语序一定是陈述句语序.例如：
I wondered if/whether he would come to meet me on time .
注意:
1)if 与whether一般是可以互换的,但在引导由选择疑问句变来的宾语从句时,只可以用whether.
I don't know whether the pen is his or yours.
2)如果宾语从句有or not,也只能用whether引导
I wonder whether he will come to my birthday party or not.
3)由连接代词或副词（who,whose,what,which,when,where,why,how)引导的宾语从句
He wondered what had happened to her.
Can you tell me where the nearest post office is?
二、宾语从句语序
宾语从句要用陈述语序,特别是由疑问句变来的宾语从句要将助动词、系动词移至主语之后或与它的谓语动词合并
“Where do you come from?”he asked.=He asked where you came from.
I don't know what the weather is like there.
三、时态呼应
1.若主句为一般现在时态或一般将来时态,从句的时态不限,可视句子而定,使用所需的任何时态.
We all know chickens can't swim.
She says she will come back.
2.若主句是祈使句,从句也可用所需的任何时态
Show me which picture is yours.
3.主句是一般过去时态,从句必须用过去完成时态
I knew she had swept the floor already.
4.若从句叙述的是客观真理、自然现象或永恒不变的规律时,则不受主句时态限制,仍用一般现在时态.
Our physics teacher told us that light travels faster than sound.
She said one and two is three.
四、否定转移
如果在动词think,believe,suppose,guess之后的宾语从句是由that引导的否定从句,且主句是第一人称,否定要转移到主句上.
I don't believe he is a boy of five years old.
I don't think you are right.
五、标点符号
宾语从句的句末用问号还是句号,取决于主句,若主句是陈述句或祈使句,句末用句号；若主句是一般疑问句,句末用问号
I don't know what you are thinking about.
Can you tell me how much the sweater cost?
六、插入语
如果主句的谓语动词是think,say等且一般为疑问句,其后的从句又是由连接代词或连接副词引导时,须将主句插入到从句中,置于疑问词之后
Who do you think is the most beautiful girl in our school?
七、简化
宾语从句可以简化为不定式短语、复合宾语或疑问词+不定式等结构,从而变为简单句
We decided that we would plant trees near the river.=We decided to plant trees near the river.
I don't know where i should start.=I don't know where to start.