一.先行詞對定語從句中的動詞的制約。

1. I , who am you friend, will help you certainly.

學習者受疑問句Who is that man? Who is coming?　等的影響，在定語從句中也用is，忘記了先行詞是I，后面的動詞應為am。

2. He is one of the teachers who know French in our school.

在定語從句的習慣使用中，one of后面的名詞是復數，這個復數名詞制約后面的定語從句的謂語動詞，因而know不作加s. 而在one of 前面有the或 the only時，后面引導的定語從句中的謂語動詞則用單數形式。如：

3. He is the only one of the teachers who knows French in our school.

而在現(xiàn)代英語中我們也可以見到在one of 加名詞復數的后面定語從句作單數動詞的情況：

4. This is one of those novels which begins with an idea.

然而在測試中我們還是按習慣用復數動詞為宜。

二.主句和從句的時態(tài)可以不一致

5.Tom, who is my friend , came to see me yesterday.

在定語從句中，據需要可以用一般現(xiàn)在的狀態(tài)，如who is my friend這個從句中，就要用現(xiàn)在時。初學者往往以為主句用過去時，則從句也用過去時。實際上主句和從句的時態(tài)是根據意義需要來決定的而不同。

三.在從句中使用了多余的代詞

6、I’ll give you the book which you’ll find it interesting.

定語從句中的it是多余的，因為which 已經代表了the book 在定語從句中做了find 的賓語。不能又it來做它的賓語。

四.漏了關系詞

7.I met the man stole my watch.

受漢語影響，學生的練習中經常寫出這類句子。英語的一般特點就是如果有從句出現(xiàn)，從句要有引導詞引導這從句。只有個別的句子才有省略引導詞的，一般是不宜省略引導詞的。

五.漏了應帶的介詞

8.Let’s find a room which we can put our things in.

在先行詞需要在定語從句中作介詞的賓語時，這個介詞是不能漏的，如此句中的in。因此在學習中先要明確先行詞在定語從句中是做主語還是做狀語。在這句中room在定語從句中是做put in 的賓語的，如果在這句中的room要做定語從句的地點狀語，則關系詞which改為where也可。

介詞是在先行詞為time, place, way等等時才有省略。

六.分清介詞是屬于哪一部分的

9. This is the town that she lived in Germany when she was young.

在she lived in Germany里有介詞in,但它不是lived in the town的結構，而是the town in Germany的結構，也就是說in是后面的，那么lived后面就少了一個in. 正確的可以是：

10. This is the town where she lived in Germany when she was young.

11. This is the town which she lived in in Germany when she was young.

七.分不清先行詞是在從句中做主語還是做賓語

12. This is the house where they lived last year.

13. This is the house (which/that) they built last year.

在12句中house在定語從句中做地點狀語，所以關系詞用where; 在13句中house在定語從句中做賓語所以用which/ that 或者省略。

14. This is the time when we left.

15. This is the time that reminded us of the happy life in out school.

在14句中，time在定語從句中做了時間狀語，而在15句中，time則做了主語。所以用的引導詞不同。

八.分不清定語從句還是其他從句

a. 定語從句還是狀語從句

16. Here is such a big stone as no one can move.

17. Here is so big a stone as no one can move.

18. Here is such a big stone that no one can move it

19. Here is so big a stone that no one can move it.

在16，17句中as 都在定語從句中做了move 的賓語，as是引導詞，引導定語從句，而在18，19句中，that 上作來引導狀語從句的。

20.I’ll go to the place where you stay.

21. I’ll go where you stay.

在句20中where是引導定語從句，而在句21 中where是引導在點狀語從句的。

b. 定語從句還是主語從句

22. As is known to all, they are sure to win.

23. It’s known to all that they are sure to win.

在句22中as是關系代詞，代表后面的整個句子做主句的主語。在句23中it是代詞，代表that引導的句子做主句的主語。

九.看不出插入句部分，以為是定語從句，影晌句中動詞的選擇

24. I met a man who I thought _____ to help us.

a. would come b. of coming c. to come d. come

許多學生一看though馬上就想起think of doing sth而選了c. 然而在這里I thought是一個插入成份，如果將其省掉就容易看出who是后面的主語了。同樣who也不會用whom 了。

分辨不出限制性定語從句，非限制性定語從句有一些分別：

25. All the books here, which have beautiful pictures in them, were written by him.

26. All the books here which have beautiful pictures in them were written by him.

句25 一般表示所有的書都是他寫的。句26則表示所有有圖畫的書是他寫的。

27. My father, who works in Shanghai, writes to me twice a month.

28. My father who works in Shanghai writes to me twice a month.。

同樣27，28一般的情況下是略有不同意義的。想想下句,如無逗號意義怎樣。

29。He sent a letter to his wife, who works in the south of China.

十.冠詞處理不好

學習者往往以為定語從句是對前面的名詞有限定作用，那么則是特指了，先行詞如有寇詞則一定是the了，其實不然。

30. A sailor is a man that works in a ship。

31. He is the man that helped me yesterday。

要知道，有的定語從句只是對前面的名詞作說明或解釋。句30的定語從句是對行詞作說明，說水手是一種。。。人，那是泛指的，不用the。而句31的定語從句是才特指的。

32 Is this factory_______ you visited last year?

a. the one c. that c. which d. where

33. Is this the factory_______ you visited last year?

a. the one c. that c. who d. where

十一。獨立句與定語從句分不清

34. I met twenty students, some of whom are good at maths.

35. I met twenty students. Some of them are good at maths.

36. We reached the mountain, on the of which we saw a beautiful scene

37. We reached the mountain. On the of it (or: On its top ) we saw a beautiful scene

34 和36是主句和定語從句關系，所以我們要用關系代詞，而在35，37各兩句中，它們是各自的獨立句子，所以用代詞。當然在36中將on the top of which改為on whose top,則定語從句的關系 更為明顯。

十二。分不清同位語還是定語從句

38. We heard the news that pleased everyone.

39. We heard the news that our term had won.

在這里要認清楚定語從句的關系詞在從句中起句子成份作用，而同位語的that 不充當句子成份，句38中的that就充當了從句中的主語，在句39中that卻不在從句中充當任何成份。再者同位語從句引導詞還可以由其他的詞來引導。如：

40. I have no idea what he going to do.

41. I have no idea whether he will come.

42. I have no ides where he will go.

十三。關于復合關系代詞whoever, whatever等等

43.Whoever get the job will have a lot of work to do.

44. Whoever gets the job, he will have a lot of work to do.

45. Whatever she says goes.

46. Whatever she says, it goes.

在句43中whoever=anyone that 即有定語從句的意味，在句45中whatever=anything that也有定語從句的意味。而在44和46句中的whoever和whatever則是引導狀語從句，所以它們后面的句子都有主語。

十四。定語從句與what引導的名詞性從句的轉換

47. He’s not the man that he was.

48. He’s not what he was.

49. China is no longer the country that it was.

51. China is no longer what it was.

我們常用名詞+that改變成what的形式，如47，48句，它們的意義基本上是一樣的，只不過用名詞+that更為清晰。49，50句也是如此。