名词性从句分为主语从句、宾语从句、表语从句和同位语从句。
其他从句还有定语从句(关键)，状语从句。
定语从句：一、结构先行词+关系词+从句二、关系词关系词分为关系代词和关系副词关系代词：that ，which ，who ,whom ,whose关系副词：where (=in/on/at which) ，why (= for which) ,when (=in/on which) 例句：1. The man who/that is standing here is Tom.2.The man that/who/whom/或者省略he is talking to is Tom.3. The man to whom he is talking is Tom.(介词后必须加宾格并且不能省略)4. The man , whose father is a teacher went abroad.5.The man ,the father of whom is a teacher went abroad.6.The man, of whom the father is a teacher went abroad.总结：……., whose +n….和….., the n of which(指物)/whom(指人)…以及…, of which/whom the n 这三个句型可以相互转换。
三、只能用that不能用which的情况1.既有人又有物：the teachers and the schools that….2.有不定代词或者有不定代词修饰时：I will tell you everythin g that….I will tell you all the things that….3.最高级修饰或者序数词修饰时：The most beautiful flowers that….The first man that…4.避免重复Who is the man that is standing here?Which is the book that I like?5.有only/very/just then 修饰时He is the only one that/who is fit for …This is the only book that I want to buy.6.先行词充当表语时Tom isn’t the boy that he used to be.(定语从句，先行词boy在句子中作为表语)Tom isn’t what he used to be.(表语从句)四、只用which不能用that的情况1.非限制性定语从句（用逗号隔开的一般是非限制性定语从句）These apple trees，which I planted three years ago，have not borne any fruit.2.介词后用whichThere are 30 chairs in the small hall, most of which are new.3.避免重复The clock is that which tells the time.五、只用who不用that1.先行词为指人的代词：those , all ,one ,ones ,someone ,anyone ,no oneThose who win the game will get the prize.All who went there spoke highly of the park.2.there be 中先行词为人是只用whoThere is an old man who wants to see you.六、特殊的关系词as1.as 引导限制性定语从句时，一定充当主语或宾语或者表语。
She wear the same coat as her sister usually does.It is such an interesting film as we all like to see.(定语从句不完整，as充当宾语)It is such an interesting film that we all like to see it.(从句结构完整，这是状语从句)2.as引导非限制性定语从句As was expected ,he finished the task perfectly.The earth is around ,as we all know.The earth , as we all know , is around.As i s often the case,…..(情况往往是这样的)As is natural,….(很自然的)这些短语可以用于议论文写作。
七、特殊句型先行词充当主语时，注意主谓一致。
1.the number of the people who own cars is increasing.2.he is one of the students who have passed examination.He is the one of the students who has passed examination.3.i have two sisters, neither of whom are teachers.I have two sisters and neither of them are teachers.I have two sisters, neither of them teachers.4.there are some people in the garden ,whose owner was seated/sitting.there are some people in the garden ,it’s owner seated/sitting.there are some people in the garden and it’s owner was seated.5.is this the factory that/which/或者省略you visited yesterday?Is this the factory to which you paid a visit?Is this the factory where you worked?Is this the factory, the one which/that/可以省略you visited?Is this the factory, the one to which you paid a visited?Is this the factory, the one where/in which you worked?6.the house whose roof was damaged has been repaired now.The house , the roof of which was damaged has been repaired now.The house of which the roof was damaged has been repaired now.7.This is the reason why/for which I did it.This is the reason that/which he told me.8.I hate the way in which/that/可以省略he spoke to his father.(way句子中作状语)That‘s the way which/that/可以省略you told me.(way句子中作宾语)He gave me the way which/that is not practical.(way在从句中作主语)9.she is so clever a girl that she learns everything quickly.She is so clever a girl as learns everything quickly.状语从句一、时间状语从句When/while/as 都可以跟持续性动词As/when/while I was walking down the street, I meet my friend.各个连词的区别：1. when●从属连词，可以引导持续性或者短暂性动词，表明主句、从句动作同时发生或者从句动作在主句之前。
When I lived there ,I used to go to the seaside.(主从句动作同时发生)When the film ended , people went home.（从句动作在主句之前）●并列连词Be doing….when….Be about to do…. When….I was doing homework when the light went off.I was about to jump into the river when he stopped me.●表示原因、作“既然”的意思How could you expect to learn anything when you didn’t listen in class.It was foolish of you to take a taxi when you could easily walk there in 5 minutes.2.while●只引导持续性动词Don’t talk too aloud while others are working.●并列连词，作“而，却”的意思He likes pop music while I am fond of folk music.●作“尽管，虽然”的意思While I admit there are problems, I d on’t agree that they can’t be solved.3.as●主句从句动作同时发生或者交替发生，作“一边。
一边。
”，“随着。
”的意思As time goes on,…….He hurried home, looking behind as he went.4.as soon as=the moment=the minute=the instant=immediately=directly= instandlyI’ll tell him the news as soon as he comes.5.no sooner…than…=hardly/scarily/barely…when…倒装句，主句用had done过去完成时。