时态

　　含宾语从句的复合句，主、从句谓语动词的时态呼应应包括以下三点内容：

　　1)如果主句的谓语动词是一般现在时，从句的谓语动词可根据需要，选用相应的任何时态。I don't know when he will come back.我不知道他将何时回来。(从句为将来时)He tells me that his sister came back yesterday.他告诉我他姐姐昨天回来了。(从句为过去时)

　　2)如果主句的谓语动词是过去时，宾语从句的谓语动词只可根据需要，选用过去时态即一般过去时、过去进行时、过去将来时或过去完成时的某一种形式。如：She asked me if I knew whose pen it was.(从句为过去时)He said that he was listening to the music at that time.(从句为过去进行时)

　　3)如果宾语从句所表示的是客观事实、普遍真理、自然现象或习惯性动作等，不管主句用什么时态，从句时态都用一般现在时。The teacher said that the earth goes round the sun.老师说地球绕着太阳转。

　　4)从句中有具体时间状语，即使从句动作发生在主句动作前，仍用一般过去时。The teacher told me she was born in 1960.

　　注意：if和when既可以引导宾语从句，也可以引导状语从句，应注意它们在两种从句中的意思和用法的不同。if和when引导宾语从句时，分别意为“是否”和“何时”，其时态应和主句时态相呼应;它们引导状语从句时，意思分别为“如果，假如”和“当……时候”，当主句时态是一般将来时时，其时态用一般现在时。它们常常放在含有状语从句和宾语从句的题干中进行综合考查。Do you know when he will come back tomorrow ?你知道他明天什么时候回来吗?Sorry，I don't know.When he comes back，I'll tell you.对不起，不知道。当他回来了，我将告诉你。I don't know if he will come.我不知道他是否会来。He will come if it doesn't rain.如果不下雨，他会来的。

　　简化宾语从句常用六法

　　同学们常会遇到把含有宾语从句的复合句转化为简单句，使其与原句意思相同(或相近)的试题。

　　下面就介绍几种常用的简化宾语从句的方法：

　　方法一：当主句谓语动词是hope， decide， wish， choose， agree， promise等，且宾语从句的主语与主句主语一致时，宾语从句可简化为不定式结构。Li Ming hopes he will be back very soon. →Li Ming hopes to be back very soon.

　　We decided that we would help him. →We decided to help him.

　　方法二：当主句谓语动词是know， learn， remember， forget， tell等动词，且主句主语与从句主语一致时，宾语从句可简化为“疑问词+不定式”结构。

　　She has forgotten how she can open the window. →She has forgotten how to open the window.注：当主句谓语动词是tell， ask， show， teach等动词，且后带双宾语，从句主语和间接宾语一致时，宾语从句可简化为“疑问词+不定式”结构。Could you tell me how I can get to the station? →Could you tell me how to get to the station?

　　方法三：当主句的谓语动词是order(命令)，require(需要)等时，如果主句和从句的主语不一致，宾语从句可简化为“名词(代词)+不定式”结构。The headmaster ordered that we should start at once.→ The headmaster ordered us to start at once.

　　方法四：某些动词后的宾语从句，可以用介词加动名词(短语)等其他形式简化。He insisted that he should go with us. →He insisted on going with us.

　　The poor boy doesn’t know when and where he was born. →The poor boy doesn’t know the time and the place of his birth.

　　方法五：某些动词后面的宾语从句可转化为“宾语+V-ing形式(作宾语补足语)”结构。Liu Ping found that there was a wallet lying on the ground. → Liu Ping found a wallet lying on the ground.

　　方法六：动词seem后的宾语从句，也可以用不定式(短语)来简化，但句型需要进行适当的变化。It seemed that the boys were going to win. →The boys seemed to win.

　　除上述方法外，还有一些特殊句式的转化。I found that it was difficult to learn English well. →I found it difficult to learn English well.

　　Soon we found that the ground was covered with thick snow. →Soon we found the ground covered with thick snow.

　　They found that the box was very heavy. →They found the box very heavy

　　口诀

　　宾语从句三姊妹,that，if/whether,wh-/how展风采

　　展风采有三关，引导词、语序、时态在把关主从时态要一致，陈述语序永不变陈述请你选that，疑问需用if/whether连特殊问句作宾从，原来问词不用换三关过后莫得意，人称、标点需注意留意变脸的if/when，从句的简化记心间