Chuyên đề luyện thi Tốt nghiệp THPT và luyện thi Đại học - Chuyên đề: Câu điều kiện

CHUYÊN ĐỀ LUYỆN THI TỐT NGHIỆP THPT VÀ LUYỆN THI ĐẠI HỌC, CAO ĐẲNG 2009
Môn: TIẾNG ANH Chuyên đề: CÂU ĐIỀU KIỆN
I.	MỤC ĐÍCH CHUYÊN ĐỀ
- Đây là một trong những chuyên đề cơ bản và rất quan trọng. Các em cần nắm được cấu trúc của các loại câu điều kiện, các biến thể của chúng, cách sử dụng và những điều cần lưu ý. Học xong chuyên đề này sẽ giúp các em phân biệt được 3 loại câu điều kiện này để tránh nhầm lẫn trong cách sử dụng.
II. KIẾN THỨC CƠ BẢN
1. Câu điều kiện loại I (the conditional sentence type I)
a) Cấu trúc
Clause 1 (the simple future) + if + Clause 2 (the simple present)
b) Cách sử dụng và ví dụ
– Diễn tả sự việc có thể xảy ra ở hiện tại hoặc tương lai. Ví dụ:
I’ll visit Ho Chi Minh city if I have time. We’ll pass the exam if we work hard.
c) Các biến thể cơ bản
-	Clause 1 (might/do +V) + if + Clause 2 (the simple present)
Î để chỉ khả năng khách quan
Ví dụ: It’s sunny. We may get a headache if we go out without a hat.
-	Clause 1 (may/can + V) + if + Clause 2 (the simple present)
Î để chỉ sự cho phép
Ví dụ: You can go home if you finish your test.
-	Clause 1 (must/should + V) + if + Clause 2 (the simple present)
Î để chỉ yêu cầu, đề nghị.
Ví dụ: You must do exercises if you want to get good marks.
d) Unless = if .not.
Ví dụ:
-	I won’t visit you if I don’t have time
Î Unless I have time, I won’t visit you.
-	We’ll go camping if the weather is fine.
Î Unless the weather is fine, we won’t go camping.
-	If you miss seeing the first part of the film, you can’t say you understand it.
Î Unless you see the first part of the film, you can’t say you understand it.
Chú ý: mệnh đề chứa “unless” không dùng dạng phủ định.
2. Câu điều kiện loại II (the conditional sentence type II)
a) Cấu trúc
Clause 1 (would + V) + if + Clause 2 (the simple past tense)
b) Cách sử dụng và ví dụ
– Diễn tả sự việc không có thật ở hiện tại hoặc tương lai
Ví dụ:
If it were cold now, we wouldn’t switch on the fans. (but it’s hot and we have to switch on the fans)
I would fly if I were a bird.
(but I am not a bird and I can’t fly)
Chú ý: Chúng ta dùng “were” cho tất cả các ngôi, không dùng “was”
c) Các biến thể
Clause 1 (might/ could + V) + if + Clause 2 (the simple past tense)
Î chỉ khả năng
Ví dụ: He might succeed if he tried
I could speak French well if I lived in France.
3. Câu điều kiện loại III (the conditional sentence type III)
a) Cấu trúc
Clause 1 (would have + P2) + if + Clause 2 (the past perfect)
b) Cách sử dụng và ví dụ
– Câu điều kiện loại III là câu điều kiện không có thật ở quá khứ. Ví dụ:
a. Miss Phuong wouldn’t have won the prize if she hadn’t attended the beauty contest.
(but the fact that she attended and she won the prize)
b. We would have got good marks if we had prepared our last lesson carefully.
(but the fact that we didn’t prepare our last lesson carefully and we didn’t get good marks).
c) Các biến thể
-	Clause 1 (could have + P2) + if + Clause 2 (had + P2)
Î chỉ sự chủ quan, sự cho phép.
Ví dụ: I could have won a prize if I had taken part in the competition last week.
You could have gone to the cinema if you had finished your homework last night.
-	Clause 1 (might have + P2) + if + Clause (had + P2)
Î chỉ khả năng khách quan.
Ví dụ: The last crop might have been better if it had rained much.
4. Câu điều kiện hỗn hợp loại II và III (the mix conditional sentence type II & III)
a) Cấu trúc
Clause 1 (would + V) + if + Clause 2 (had + P2)
b) Ví dụ
If I had been born in town, I would like life there.
(the fact that I wasn’t born in town, so I don’t like life there now) If I followed your advice, I would have a job now.
(the fact that I didn’t follow your advice, so I don’t have a job now)
c) But for + điều kiện loại II, III
But for: nếu không có Ví dụ:
-	You help me everyday so I can finish my work.
Î But for your daily help, I couldn’t finish my work.
-	She encouraged him and he succeeded.
Î But for her encouragement, he wouldn’t have succeeded.
-	The teacher explained and we understood.
Î But for the teacher’s explanation, we wouldn’t have understood.
5. Đảo ngữ của câu điều kiện
a) Đảo ngữ của câu điều kiện loại I
-	Nếu trong câu có “should” ở mệnh đề if, thì đảo “should” lên đầu câu
If he should ring , I will tell him the news.
Î Should he ring, I will tell him the news.
-	Nếu trong câu không có “should”, chúng ta phải mượn “should” If he has free time, he’ll play tennis.
Î Should he have free time, he’ll play tennis. If she comes early, we’ll start.
Î Should she come early, we’ll start.
b) Đảo ngữ của câu điều kiện loại II
-	Nếu trong câu có động từ “were”, thì đảo “were” lên đầu.
If I were a bird, I would fly.
Î Were I a bird, I would fly.
They would answer me if they were here.
Î Were they here, they would answer me.
-	Nếu trong câu không có động từ “were” thì mượn “were’ và dùng “ to V” If I learnt Russian, I would read a Russian book.
Î Were I to learn Russian, I would read a Russian book. If they lived in Australia now, they would go swimming.
Î Were they to live in Australia now, they would go swimming.
-	Đảo trợ động từ của thì quá khứ hoàn thành.
If it had rained yesterday, we would have stayed at home. Î Had it rained yesterday, we would have stayed at home. If he had trained hard, he would have won the match.
Î Had he trained hard, he would have won the match.
-	Chú ý: ở dạng phủ định, “not” được đặt sau chủ ngữ: Had it not been so late, we would have called you.
III. CỦNG CỐ KIẾN THỨC
Bài tập1: Chia động từ trong ngoặc theo đúng dạng
1. Bring him another if he (not/like) this one.
2. She (be) angry if she (hear) this tomorrow.
3. Unless you are more careful, you (have) an accident.
4. If you (like), I (get) you a job in this company.
5. If grandmother (be) 5 years younger, she (play) some games.
6. If he sun (stop) shinning, there (be) no light on earth.
7. If I (be) a millionaire, I (live) on Mars.
Bài tập 2: Viết lại câu theo gợi ý
1. I didn’t eat lunch, I feel hungry now.
Î If I.
2. If it hadn’t rained, we would have a better crop.
Î But for
3. If you want my advice, I wouldn’t buy it.
Î If I 
4. I only come if they invite me.
Î Unless.
5. He didn’t revise all his lessons, he failed the exam.
Î If he
6. His sister sent her money, so he continued to study.
Î But for
7. The park is over there, only 5 minutes’ walk.
Î If you walk.
8. In case it rains, we’ll stay at home
Î If it..
Bài tập 3: Sửa các câu sai sau:
1. Should anyone rang, could you take a message?
2. Were the customers not complained, nothing would have been done.
3. Was I a bird, I would fly.
4. Unless you don’t have a good command of English, you won't be able to work for this company.
5. Were they live in Australia now, they would go swimming.
Đáp án:
Bài 1:
1. Bring him another if he doesn’t like this one.
2. She will be angry if she hears this tomorrow.
3. Unless you are more careful, you will have an accident.
4. If you like, I will get you a job in this company.
5. If grandmother were 5 years younger, she would play some games.
6. If the sun stopped shinning, there would be no light on earth.
7. If I were a millionaire, I would live on Mars.
Bài 2:
1. I didn’t eat lunch, I feel hungry now.
Î If I had eaten lunch, I wouldn’t feel hungry now.
2. If it hadn’t rained, we would have a better crop.
Î But for rain, we would have a better crop.
3. If you want my advice, I wouldn’t buy it.
Î If I were you, I wouldn’t buy it.
4. I only come if they invite me.
Î Unless they invite me, I won’t come.
5. He didn’t revise all his lessons, he failed the exam.
Î If he had revised all his lessons, he wouldn’t have failed the exam.
6. His sister sent her money, so he continued to study.
Î But for his sister’s money, he wouldn’t have continued to study.
7. The park is over there, only 5 minutes’ walk.
Î If you walk to the park, it will take you 5 minutes.
8. In case it rains, we’ll stay at home
Î If it rains, we’ll stay at home.
Bài 3:
1. Rang Î ring
2. Were Î had
3. Was Î were
4. You don’t have Î you have
5. Were they live Î were they to live
IV. BÀI TẬP VỀ NHÀ
Bài tập 1: Viết lại câu sau dựa vào từ cho sẵn:
1. I'll buy a new hat. I'll give it to you.
If 	.
2. Today isn't Sunnday. The pupils can't go swimming.
If 	.
3. He wasn't here. He didn't have a lot of fun.
If 	.
4. My brother will have anough money. He will buy a bicycle.
If 	.
5. He didn't have time. He didn't read this novel.
If 	.
6. Because she missed the bus, she was late.
If 	.
7. Peter doesn't study hard, so he can't get good marks.
If 	.
8. My sister is absent from her class because she has a terrible headache.
If 	.
9. Windy didn't come, so we cancelled the meeting.
If 	.
10. He was angry, so he didn't say anything.
If 	.
Bài tập 2: Chia động từ trong ngoặc
1. If it had not rained, we (go) 	 camping.
2. If he (speak) 	 more slowly, I could have understood him.
3. What 	you (do) 	 if you were a mokey?
4. If he had listened carefully, he (perform) 	well in his examination.
5. If I find your book, I (give) 	 it to you.
6. If you came with us, you (have) 	 a good time.
7. If I (not/miss) 	 the bus, I could have come early.
8. If I took a trip this summer, I (go) 	 to DatLat.
9. If he (not/steal) 	 the wallet, he (not/be) 	 in prison now.
10. If they (invite) 	 yesterday, I (be) 	 is a good day tomorrow.
11. We (go) 	 swimming if it (be) 	 a good day tomorrow.
12. If the weather (be) 	 nice last day, I (go) 	 for a walk.
13. My dog always barks if he (hear) 	 anything unusual.
14. If he (not/ do) 	 come soon, I'm not going to wait.
15. If the phone (ring) 	, can you answer it?
16. If it rains this evening, I (not/will) 	 go out.
17. If she (come) 	, she will ghe a surprise.
18. If we had had enough money, we (buy) 	 that house.
Giáo viên: Lê Kim Tường