I. CÁC ĐẠI TỪ QUAN HỆ:
1. WHO:
– Làm chủ từ trong mệnh đề quan hệ
– Thay thế cho danh từ chỉ người
[ … N (person) + WHO + V + O ]
2. WHOM:
– Làm túc từ cho động từ trong mệnh đề quan hệ
– Thay thế cho danh từ chỉ người
[ … N (person) + WHOM + S + V ]
3. WHICH:
– Làm chủ từ hoặc túc từ trong mệnh đề quan hệ
– Thay thế cho danh từ chỉ vật
[ … N (thing) + WHICH + V + O ]
[ … N (thing) + WHICH + S + V ]
4. THAT:
– Có thể thay thế cho vị trí của who, whom, which trong mệnh đề quan hệ quan hệ xác định.
5. WHOSE: dùng để chỉ sở hữu cho danh từ chỉ người hoặc vật, thường thay cho các từ: her, his, their, hoặc hình thức ‘s.
[ … N (person, thing) + WHOSE + N + V … ]
II. CÁC TRẠNG TỪ QUAN HỆ:
1. WHY: mở đầu cho mệnh đề quan hệ chỉ lý do, thường thay cho cụm for the reason, for that reason.
[ … N (reason) + WHY + S + V … ]
Ex: I don’t know the reason. You didn’t go to school for that reason.
→ I don’t know the reason why you didn’t go to school.
2. WHERE: thay thế từ chỉ nơi chốn, thường thay cho there
[ … N (place) + WHERE + S + V … ]
(WHERE = ON / IN / AT + WHICH)
Ex: a/ The hotel wasn’t very clean. We stayed t that hotel.
→ The hotel where we stayed wasn’t very clean.
→ The hotel at which we stayed wasn’t very clean.
3. WHEN: thay thế từ chỉ thời gian, thường thay cho từ then
[ … N (time) + WHEN + S + V … ]
(WHEN = ON / IN / AT + WHICH)
Ex: Do you still remember the day? We first met on that day.
→ Do you still remember the day when we first met?
→ Do you still remember the day on which we first met?
I don’t know the time. She will come back then.
→ I don’t know the time when she will come back.
III. CÁC LOẠI MỆNH ĐỀ QUAN HỆ:
Có hai loại mệnh đề quan hệ: mệnh đề quan hệ xác định và mệnh đề quan hệ không xác định.
1.     Mệnh đề quan hệ xác định (Defining relative clauses): là mệnh đề được dùng để xác định danh từ đứng trước nó. Mệnh đề xác định là mệnh đề cần thiết cho ý nghĩa của câu, không có nó câu sẽ không đủ nghĩa. Nó được sử dụng khi danh từ là danh từ không xác định và không dùng dấu phẩy ngăn cách nó với mệnh đề chính.
Ex: The city which I visited last summer is very beautiful.
(Defining relative clause)
2.      Mệnh đề quan hệ không xác định (Non-defining relative clauses): là mệnh đề cung cấp thêm thông tin về một người, một vật hoặc một sự việc đã được xác định. Mệnh đề không xác định là mệnh đề không nhất thiết phải có trong câu, không có nó câu vẫn đủ nghĩa. Nó được sử dụng khi danh từ là danh từ xác định và được ngăn cách với mệnh đề chính bằng một hoặc hai dấu phẩy (,) hay dấu gạch ngang (-)
Ex: Dalat, which I visited last summer, is very beautiful.
(Non-defining relative clause)
Note: để biết khi nào dùng mệnh đề quan hệ không xác định, ta lưu ý các điểm sau:
– Khi danh từ mà nó bổ nghĩa là một danh từ riêng
– Khi danh từ mà nó bổ nghĩa là một tính từ sở hữu (my, his, her, their)
– Khi danh từ mà nó bổ nghĩa la một danh từ đi với this , that, these, those
IV. MỘT SỐ LƯU Ý TRONG MỆNH ĐỀ QUAN HỆ:
1. Nếu trong mệnh đề quan hệ có giới từ thì giới từ có thể đặt trước hoặc sau mệnh đề quan hệ (chỉ áp dụng với whom và which.)
Ex: Mr. Brown is a nice teacher. We studied with him last year.
→ Mr. Brown, with whom we studied last year, is a nice teacher.
→ Mr. Brown, whom we studied with last year, is a nice teacher.
2. Có thể dùng which thay cho cả mệnh đề đứng trước.
Ex: She can’t come to my birthday party. That makes me sad.
→ She can’t come to my birthday party, which makes me sad.
3. Ở vị trí túc từ, whom có thể được thay bằng who.
Ex: I’d like to talk to the man whom / who I met at your birthday party.
4. Trong mệnh đề quan hệ xác định , chúng ta có thể bỏ các đại từ quan hệ làm túc từ: whom, which.
Ex: The girl you met yesterday is my close friend.
The book you lent me was very interesting.
5. Các cụm từ chỉ số lượng some of, both of, all of, neither of, many of, none of … có thể được dùng trước whom, which và whose.
Ex: I have two sisters, both of whom are students.
She tried on three dresses, none of which fitted her.
V. CÁCH RÚT GỌN MỆNH ĐỀ QUAN HỆ:
1. Mệnh đề quan hệ được rút thành cụm phân từ:
Mệnh đề quan hệ chứa các đại từ quan hệ làm chủ từ who, which, that có thể được rút gọn thành cụm hiện tại phân từ (V-ing) hoặc quá khứ phân từ (V3/ed).
* Nếu mệnh đề quan hệ là mệnh đề chủ động thì rút thành cụm hiện tại phân từ (V-ing).
Ex: a/ The man who is standing over there is my father.
→ The man standing over there is my father.
b/ The couple who live next door to me are professors.
→ The couple living next door to me are professors.
* Nếu mệnh đề quan hệ là mệnh đề bị động thì rút thành cụm quá khứ phân từ (V3/ed).
Ex: a/ The instructions that are given on the front page are very important.
→ The instructions given on the front page are very important.
b/ The book which was bought by my mother is interesting.
→   The book bought by my mother is interesting.
2. Mệnh đề quan hệ được rút thành cụm động từ nguyên mẫu:
Mệnh đề quan hệ được rút thành cụm động từ nguyên mẫu (To-infinitive) khi trước đại từ quan hệ có các cụm từ: the first, the second, the last, the only hoặc hình thức so sánh bậc nhất.
Ex: a/ John was the last person that got the news.
→    John was the last person to get the news.
b/ He was the best player that we admire.
→   He was the best player to be admired.
c/ He was the second man who was killed in this way.
→   He was the second man to be killed in this way.
10 TRƯỜNG HỢP DÙNG ‘THAT’ KHÔNG DÙNG WHICH.
1. Phía trước là “all, little, much, few, everything, none ” thì dùng “that” mà không dùng “which”.
Ex: There are few books that you can read in this book store.
(Có một vài cuốn sách mà bạn có thể đọc ở tiệm sách này).
2. Từ được thay thế phía trước vừa có người vừa có vật thì dùng “that” mà không dùng “which”.
Ex: He asked about the factories and workers that he had visited.
(Ông ấy hỏi về những công ty và công nhân mà ông ấy đã đến thăm)
3. Từ được thay thế phía trước có định ngữ là tính từ ở cấp so sánh nhất thì dùng “that” mà không dùng “which”.
Ex: This is the best novel that I have ever read.
(Đây là cuốn tiểu thuyết hay nhất mà tôi từng đọc).
4. Từ được thay thế phía trước có định ngữ là số thứ tự thì dùng “that” mà không dùng “which”.
Ex: The first sight that was caught at the Great Wall has made a lasting impression on him.
(Cảnh tượng đầu tiên về Vạn lý trường thành đập vào mắt ông ấy gây được ấn tượng khó quên với ông).
5. Từ được thay thế phía trước có định ngữ là “the only, the very, the same, the right” thì dùng “that” mà không dùng “which”.
Ex: It is the only book that he bought himself.
(Đó là cuốn sách duy nhất mà anh ta đã tự mình mua).
6. Từ được thay thế phía trước có định ngữ là “all, every, any, much, little, few, no” thì dùng “that” mà không dùng “which”.
Ex: You can take any room that you like.
(Anh có thể lấy bất cứ phòng nào mà anh thích).
– There is no clothes that fit you here.
(Ở đây chẳng có bộ quần áo nào phù hợp với bạn cả).
7. Trong câu hỏi (Mệnh đề chính) mở đầu bằng “which” thì dùng “that” mà không dùng “which” làm từ nối.
Ex: Which of the books that had pictures was worth reading?
(Những cuốn sách có tranh ảnh thì đáng đọc đúng không?)
8. Trong câu nhấn mạnh “It is … that …” thì dùng “that” mà không dùng “which” làm từ nối .
Ex: It is in this room that he was born twenty years ago.
(Cách đây hai mươi năm chính trong căn phòng này ông ấy đã được sinh ra).
9. Trong câu dùng cấu trúc “such (the same) … as …” dùng từ nối “as” không dùng “which”.
Ex: We need such materials as can bear high temperature.
(Chúng tôi cần những vật liệu có thể chịu được nhiệt độ cao như thế này).
10. Diễn tả ý “giống như…..” dùng từ nối “as” không dùng “which”.
Ex: Mary was late again, as had been expected.
(Mary lại đi muộn, như đã được dự kiến)
2 TRƯỜNG HỢP KHÔNG DÙNG ‘THAT’:
– Trong mệnh đề quan hệ không xác định
– Sau giới từ.
1. Mr. Ken, …………. is living next door, is a dentist.
A. that           B. who            C. whom             D. what
2. The man ………….she wanted to see her family.
A. which           B. where             C. whom          D. who
3. The woman ………….came here two days ago is her professor.
A. who              B. that                 C. whom            D. what
4. Freedom is something for ………….millions have given their lives.
A. which            B. where              C. whom           D. who
5. Blair has passed the exam last week, ………….is great news.
A. who                B. that                   C. which             D. whom
6. The film about ………….they are talking about is fantastic.
A. who                B. which                 C. whom                D. that
7. He is the boy ………….is my best friend.
A. that                B. whom                C. who                   D. A& C
8. I live in a pleasant room ………….the garden.
A. to overlook            B. overlooking                C. overlooked             D. which overlooking
9. The pilot was the only man ………….after the crash.
A.was rescued          B. rescued                   C. rescuing                      D. to be rescued

10. I’ll see you near the post office ………….we met the other day.
A. which                    B. where                      C. when                          D. why
11. The man…………. lives behind my house is a doctor.
A. that          B. who            C. which          D. whom
12. The old building………….is in front of my house fell down.
A. of which              B. which               C. whose               D. whom
13. Her computer ………….was my friend’s got broke.
A. which           B. whom            C. who             D. that
14. Her grandmother, ………….is 70, often takes exercise.
A. what             B. who                 C. where          D. which
15. The really happy people are those ……enjoy their daily work. 
A. what              B. who                  C. which             D. where
16. My girlfriend loves tokbokki, ………….is Korean food.
A. which            B. where               C. whom             D. who
17. The book ………….is in the car is his brother’s.
A. who                 B. that                   C. which              D. whom
18. Peter, ………….I played video games with on the weekend, was younger than me.
A. that             B. who            C. which               D. whom
19. The people ………….for the bus in the rain are getting well.
A. waiting              B. to wait                          C. waited                     D. wait
20. I have a message for people ………….by the traffic chaos.
A. to delay                  B. who delay                       C. delayed                   D. who delaying
 Who, Whom, Whose, Which, That, Where…
1. The men ………….lives next-door are English.
2. Do you know the girls ………….are standing outside the church?
3. The chocolate ………..you like comes from the United States.
4. A burglar is someone ………….breaks into a house and steals things.
5. I can’t find the key ………….opens this door.
6. I don’t like the boy ………….Sue is going out with.
7. The man ………….she is going to marry is very rich.
8. He wore a mask ………….made him look like Mickey Mouse.
9. The man ………….mobile was ringing did not know what to do.
10. The woman ………….daughter was crying tried to calm her down.
11. The family ………….car was stolen last week is the Smiths.
12. A bus is a big car ………….carries lots of people.
13. Children ………….like music are often good at mathematics.
14. The girl ………….recited the poem is my niece.
15. The Pacific Ocean, ………….might have been crossed by raft during the Stone Age, is the world’s largest ocean.
16. The parents thanked the woman………….had saved their son
17. Two men, neither of ………….I had been before, came into my office.
18. He ate the food ………….no one else wanted
19. The village …………. I ran out of petrol didn’t have a petrol station
20. John sold his computer, …………. he no longer need, to his cousin
who
who
which
that
which
whom
whom
which
whose
whose
whose
which
which
which
which
who
who
who
whom
where
21. The dictionary ………….you gave me is very good.
22. The police are looking for the thieve ………….got into my house last night.
23. I have lost the necklace ………….my mother gave me on my birthday.
24. Buses ………….go to the airport run every half hour.
25. I gave you a book ………….had many pictures.
26. Did you see the beautiful dress ………….she wore yesterday.
27. This is the bank ………….was robbed yesterday.
28. He arrived with a friend ………….waited outside in the car.
29. The car ………….the robbers escaped in was a BMW.
30. The postman ………….works in the village is very old.
31. The cowboy ………….is wearing a red shirt looks very funny.
32. The volunteers, ………….enthusiasm was obvious, finished the work quickly.
33. The engineers ………….designed the building received an award.
34. The townspeople, ………….pride in their community is well- known, raised enough money to build a new town hall.
35. The newspaper to ………….we subscribe is delivered regularly.
36. The factory …………. closed last week had been there for many years
37. I like the ice-cream …………. they sell in that shop
38. John has got a new mobile phone …………. takes photos
39. The job for …………. she has applied is in London
40. Teddy has two cars, one of …………. is very expensive.
which
which
which
which
which
which
which
which
which
which
who
who
who
who
who
that
that
that
whose
whose
1. The first boy has just moved. He knows the truth.

2. They called a doctor. He lived nearby.
3. The only thing is how to go home. It make me worried.

4. Linh liked the waiter. He was very friendly.
5. He was Tom. I met him at the bar yesterday.
6. Ba dropped a cup. It was new.
7. They are looking for the man and his dog. They have lost the way in the forest.

8. I live in a city. It is in the north of Vietnam.
9. My wife wants you to come to dinner. You were speaking to my wife

10. The woman works in a hospital. She is from India.
11. The students will be awarded the present. The students’ reports are very valuable.

12. The man was rude. He was wearing a red shirt.
13. The botanist will never forget the day. He found a strange plant on that day.

14. The TV got broken. It was my grandfather’s.
15. The man works for my father’s company. The man’s daughter is fond of dancing.
The first boy who knows the truth has just moved.
They called a doctor who he lived nearby
The only thing which make me worried is how to go home.
Linh liked the waiter who was very friendly.
He whom I met at the bar yesterday was Tom
Ba dropped a cup which was new
They are looking for the man and his dog that have lost the way in the forest.
I live in a city that is in the north of Vietnam
My wife, whom you were speaking to, wants you to come to dinner.
The woman who is from India works in a hospital.
The students whose report are very valuable will be awarded the present.
The man who was wearing a red shirt was rude.
The botanist will never forget the day when he found a strange plant.
The TV that was my grandfather’s got broken.
The man whose daughter is fond of dancing works for my father’s company.
Sử dụng who/ which/ that/ where… Đặt một câu ở mệnh đề thứ hai trong những câu dưới đây
1. I went to see a doctor. She had helped my father
I went to see the doctor ……………………………………………
2. Mary was wearing the red dress. It was made in France
Mary was wearing the red dress ……………………………………………
3. John is one of my closest friends. I have known him for three years
John is one of my closest friends ……………………………………………
4. Ann talked to a man. He won a lot of money
Ann talked to the man……………………………………………
5. He is an architect. He designed the new city library
He is the architect ……………………………………………
6. A woman wrote to me. She wanted my advice
The woman ……………………………………………
7. We stayed at Sofitel hotel. Mark recommended it to us
We stayed at Sofitel hotel ……………………………………………
8. New York is one of the largest cities in the USA. My sister is living there
New York is one of the largest cities in the USA……………………………………………
9. The couple has got a married again. Their divorce was in the newspapers
The couple ……………………………………………
10. Jerry sent me a letter. It was very funny.
Jerry sent me the letter ……………………………………………
who/ that had helped my father
which/ that was made in France
whom I have known for three years
who/ that won a lot of money
who/ that designed the new city library
who/ that wrote to me wanted my advice
which/ that Mark recommended to us
where my sister is living
whose divorce was in the newspapers has got married again
that/ which was very funny
Tìm và sửa lỗi sai (nếu có) trong những câu sau đây
The film I watched yesterday was interesting.

2. The only house last week was Oanh’s.

3. A dictionary is a book gives her the meaning of words.

4. I like that dress is really beautiful.

5. Do you get on with the person lives behind?
who
who ➔ which (thay thế cho the film phải dùng which chứ không dùng who).
to be paint ➔ to be painted (sai về chia thời động từ).
to be paint
whom ➔ which (thay thế a book phải dùng which).
whom
whom ➔ which (thay thế cho that dress dùng which).
whom
which ➔ who (thay thế cho the person phải dùng who).
which