定语从句中which和that用法及need用法.doc

定语从句中which和that用法在定语从句中，which 和that 在指代事物时，一般可以互换使用，但并非在任何情况下都是这样。一、宜用that, 而不宜用which 的情况.先行词为不定代词all,much,something,everything,anything,nothing,none,the one等 1. We should do all that is useful to the people.2. Theres nothing that can be said about it.3. Do you mean the one that was bought yesterday?先行词被only, any, few, little, no, just, very, one of等词修饰时。1 .The only thing that we could do was to wait.2 .Thats the very word that is wrongly used.3 .The last place (that) we visited was the chemical works.4 .You can take any (=whichever) seat that is free.5 .I hope the little that I can will be of some help to them.先行词是序数词时或被序数词修饰时。1. When we talk about Wuxi, the first that comes into mind is Tai Lake.2. This is the third film that has been shown in our school this term.先行词是最高级或被最高级修饰时。1. This is the best that can be done now.2. The most important thing that should be done right now is how to stop him from going on.先行词既有人又有物，用which和who都不适合，这时宜用that. 如：1.The writer and his novel that you have just talked about is really well known .2.The rider and his bike that had run over an old woman were held up by the police.被修饰词为数词时. 1. Yesterday I caught two fish and put them in a basin of water .Now you can see the two that are still alive .如果有两个从句，其中一个关系代词已用which ,另一个关系代词宜用that，以避免语言的单调或重复。Edison built up a factory which produced things that had never been seen before.疑问词是who或which，关系代词宜用that，以避免重复。1. Which is the book that you like best?2. Who is the man that is standing at the gate?主句是There be 结构，修饰其主句的定语从句宜用that 作关系代词. 如：1. There is still a seat in the corner that is still free.被修饰成分为表语时，或者关系代词本身是定语从句的表语时,该关系代词宜用that . 1. Thats a good book that will help you a lot.2. My home village is no longer the place ( that ) it used to be .二、定语从句中宜用which而不宜用that 的情况:当关系代词的前面有介词时. 1.A zoo is a park in which many kinds of animals are kept for exhibition.2.Is this the room in which Mr. White lives?在非限制性定语从句中. 1.Crusoes dog, which was are now very old, became ill and died .2.More and more people are beginning to learn English, which is becoming very popular in our country. (which指代主句)在一个句子中有两个定语从句，其中一个定语从句的关系代词用了that, 另一个宜用which . 1. Let me show you the novel，that I borrowed from the library which was newly open to us. 2. At the station I bought some magazines that might help me to pass the time on the train and which I could pass on to others when I finished them.当关系代词后面带有插入语时. 1. Heres the English grammar which, as I have told you, will help improve your English.先行词本身是that, 宜用which . Whats that which she is looking at?先行词是those+复数名词. A shop should keep a stock of those goods which sell best.need用法解析一、 用作情态动词作为情态动词的need具有情态动词的一般性质，要充分阐释作为情态动词的need的用法，务必首先说明白情态动词的特征。情态动词的主要特征：没有人称和数的变化。不论主语是第几人称，不论主语是单数还是复数，情态都词都无形式变化；不能单独充当谓语。情态动词必须与一个实义动词一起构成复合谓语，并且这个实意动词要始终是动词原形。变为否定句时只需在情态动词之后加not。变为疑问句时只需将情态动词提到主语的前面。二用作实义动词 作为实义动词，need后面的宾语可以是名词、动名词、动词不定式或代词，这种情况下，need既可用于肯定句，也可用于否定句和疑问句，构成否定句和疑问句时要借助于助动词do或does.1need sth.这是need最常见的用法之一，其后的宾语可以是名词，也可以是代词。如：1). We need a great deal of money now. 我们需要和多钱。2). Does your father need any help? 你爸爸需要帮助吗?2need doing 与 need to be done need后面可跟动名词作宾语，这种情况下应注意两点：.主动形式的动名词doing具有被动的含义；.该动名词可以改为其动词不定式的被动形式而句子的意义不变。例如：3). The door needs painting. = The door needs to be painted. 那扇门需要油漆一下。4). Your car needs mending. = Your car needs to be repaired. 你的车需要维修了。3need to do sth.作为实义动词，need后面需要接带to的动词不定式,表示有义务或责任去做某事。如：5). What do we need to take for the picnic? 野餐我们需要带些什么？6). Will we need to show our passports? 我们需要出示护照吗？只要need后面跟的是动词原形，它就是情态动词，这时，变否定，只需在其后加not；变为疑问句，只需把它移主语的前面。例如：9). Need I type this letter again? 我需要重新录入将这封信吗？10). There is enough time. You neednt hurry. 有的是时间，你不必着急。11). The president wondered whether he need send more soldiers. 总统不知道他是否要增兵。12). -Must I hand in my homework now? 现在我必须交作业吗？-No, you neednt. 不，你不必。三用作名词need作为名词，含义为“缺乏，需要”；其复数表示“基本需要”。要掌握两个词组：in (great) need of（急需） 与meet the needs of(满足的需要)。例