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.