Bài 2 :CÂU ĐIỀU KIỆN (Conditional Sentence)
Một câu điều kiện có hai mệnh đề : mệnh đề chỉ điều kiện (tức mệnh đề phụ) còn
được gọi là mệnh đề có if (If-clause) và mệnh đề chỉ kết quả còn được gọi là mệnhđề chính (main clause).
- If he works harder, he will succeed in his examination.
(if-clause) (main clause) Chúng ta cũng có thể đặt mệnh đề chính ở đầu câu :
- He will succeed in his examination if he works harder.
Trong tiếng Anh có 3 loại câu điều kiện chính :
* Type I : ĐIỀU KIỆN CÓ THỂ XẢY RA ĐƯỢC (probable condition)
1/ Ý nghĩa : Loại điều kiện này dùng để diễn tả một sự việc có thể xảy ra hoặc
không thể xảy ra ở hiện tại hoặc tương lai; nhưng chúng ta có nhiều hy vọng nó xảy ra.
2/ Thì của động từ :
If- clause Main clause
Simple present Simple future (shall / will + verb)
- If the rain stops, we shall go for a walk.- He will come if you call him.
* Ngoài ra chúng ta còn có thể dùng các khiếm khuyết động từ như : CAN, MUST,MAY … để thay cho shall hoặc will ở mệnh đề chính.
- If you ask me, I can help you.
- You must study harder if you want to pass the coming exam.
* Mệnh đề chính có thể là một mệnh lệnh hoặc thỉnh cầu :
- Come to me if you need help.
- If you have time, perfect your English.
* Type II : ĐIỀU KIỆN KHÔNG CÓ THẬT Ở HIỆN TẠI (Present- unreal Con)1/ Ý nghĩa : Loại điều kiện này diễn tả một điều kiện khó có thể xảy ra hay
một sự việc không thực hiện được ở hiện tại hoặc tương lai.
Trang 2- If I had a lot of free time, I would go swimming.
(= I haven’t got free time, so I won’t go swimming)
- If Tom were here, he would know the answer.
(= Tom isn’t here, so he doesn’t know the answer.)
- I would call him if I knew his number.
(= I don’t know his number, so I won’t call him)
* Quá khứ giả định là hình thức quá khứ đơn của các động từ ngoại trừ động từ “to
be” chỉ có một hình thức WERE cho tất cả các ngôi.
* COULD, MIGHT… có thể được dùng để thay thế cho should hay would.
- If John worked hard, he could pass his exam.
* Type III : ĐIỀU KIỆN KHÔNG CÓ THẬT Ở QUÁ KHỨ (Past-unrealCondition)
1/ Ý nghĩa : Loại điều kiện này dùng để diễn tả một điều kiện hoàn toàn không
thực hiện được hoặc không xảy ra trong quá khứ.
2/ Thì của động từ :
Past perfect (Should/ would have + past participle)Perfect Conditional
- If he had had a lot of money, he would have bought a bigger house.- I would have taken you to the movie if you had come to see me yesterday.
* “If” có thể được lược bỏ đi nếu có sự đảo ngữ (thường được dùng trong hình thức
nhấn mạnh).
- Were I rich, I would help you.
(= If I were rich, I would help you.)
- Had he known the truth, he would have been very angry.
(= If he had known the truth, he would have been very angry)
* Ngoài liên từ “if” ra, câu điều kiện còn được bắt đầu bằng các liên từ khác như :
suppose, supposing that (giả sử như), on the condition that (với điều kiện là), aslong as, so long as, provided that (miễn là), in case (trong trường hợp) , even if
( ngay cho là)
- As long as you return the book by Saturday, I will lend it to you withpleasure.
* Hai tiếng có nghĩa phủ định : unless (trừ phi), but for (nếu không)
- He won’t come unless you call him.
(= He won’t come if you don’t call him.)
Trang 3- But for the storm, he would have arrived much earlier.
EXERCISE I : Rewrite the sentences , using conditional clauses.
1/ I (do) if I (have) time.
- I will do it if I have time (type 1)- I would do it if I had time (type 2)
- I would have done it if I had had time (type 3)
2/ If she (not try), she (not succeed).
Trang 4EXERCISE II: Put the verbs in brackets in correct tenses.
1/ If I (have) a typewriter, I could type it myself.
2/ If I had known that you were in hospital , I (visit) you.
3/ You could make much progress if you (attend) class regularly 4/ If I (know) his telephone number, I would give it to you 5/ If you (arrive) ten minutes earlier, you would have got a seat 6/ If he (study) harder, he can pass an exam.
7/ She may be late if she (not hurry) 8/ Tell him to ring me if you (see) him.
9/ If you (speak) more slowly,he might have understood you 10/ What (you do) if you got fat ?
Exercise III : Supply the correct verb tense.
1/ If you are kind to me, I (be) _ good to you 2/ He (come) _ if you waited.
3/ If you (ring) _ the bell, the servant would come.
4/ If I had known that the baby was hungry, I (feed) _ him 5/ If it (not, rain) _ a lot, the rice crop wouln’t grow.
6/ If today (be) _ Sunday, we wouldn’t have to work 7/ If she had had your address, she (write) _ to you.
Trang 58/ We lost the match If you (play) _ for us, we (win) _.
9/ So long as you return the book by Saturday, I (lend) _ it to you with pleasure.
10/ They would not be paid unless they (do) _ their work well.
11/ Provided he (not, be) _ interrupted, he can finish the work on time 12/ If it (be) _ convenient, let’s meet at three o’clock.
13/ If I became very rich, I (build ) _ a hospital for the poor.
14/ If he (give) _ up smoking, as his doctor orders, he will be soon well again.
15/ He (not, have) _ an accident if he had not been driving so fast 16/ If she (write) _ more carefully, she might not have made too many mistakes.
17/ You would have to stay in bed unless your health (improve) _ 18/ Did she have more practice, she (speak) _ English better 19/ Had I known that she was sick, I (visit) _ her.
20/ Supposing World War III (happen) , human civilization (be) _ destroyed.
EXERCISE IV : Put “if” or “unless” into these spaces.
1/ we hurry, we’ll miss the bus.
2/ Will you phone me you come to England ? 3/ you see Jane, ask her to contact me.
4/ You’ll never pass your exam you don’t work harder 5/ Liverpool won’t win they begin playing better.
6/ you forget our address, you can find it in the phone book 7/ You won’t pass your driving test you drive more carefully 8/ He’ll be ill he doesn’t stop worrying so much.
9/ We’ll go to the beach tomorrow it’s raining.
10/ We’ll never get there on time the train leaves soon.
EXERCISE V : Use “if” in place of “unless”
1/ We won’t go out unless it stops raining.
- 2/ I will call the police unless you give back my bicycle.
-
Trang 63/ You wouldn’t be able to do this exercise unless your English were good.
EXERCISE VI : The following sentences are first, second or third conditional Put
the verbs in brackets into the appropriate form.
1/ We wanted to go out yesterday but the weather was terrible If it (be) … had
been … a nice day, we (go) … would have gone … for a picnic.
2/ Why don’t you explain everything to him ? If you (not tell) _ him the truth, I’m sure you (regret) _ it one day.
3/ Mary was here not long ago If you (come round) _ earlier, you (see) her.
4/ Apparently, the ferry company are planning to close the port in this town If that (happen) _, the town (lose) _ a great deal of money.
5/ I (help) _ you with it if I (have) _ more time but I’m afraid I haven’t got any spare time at all at the moment.
6/ The government is expecting to win the next election, but if it (lose) _, the Prime Minister (resign) _ from politics.
7/ I am so glad that you took me to your friend’s party If we (not go) _ there, I (never meet) _ Kate Winset.
Trang 78/ It’s ridiculous that trains are so expensive If fares (be) _ cheaper, I’m sure more people (use) _ the train and leave their cars at home.
9/ If she (get) _ that job she’s applied for, she (be) _ delighted And I think she’s got a good chance of getting it.
10/ Fortunately the explosion took place at night when the streets were empty It (be) _ a disaster if it (happen) _ in the middle of the day.
11/ The talks between the two leaders keep breaking down If they (break down) _ again, it is possible that there (be) _ a war between the two countries.
12/ If Alison (know) _ anything about car mechanics, I’m sure she (help) _ us fix the car, but I think she knows even less than we do.
13/ They’ve been married for twenty years now but I don’t think she (marry) _ him if she (know) _ what a selfish man he was.
14/ Children spend too much time watching television and playing computer games I’m sure they (be) _ happier if they (spend) _ more time playing outside.
15/ James has everything he wants but he’s always moaning I’m sure that if I (have) _ so much money, I (not moan) _ all the time.
EXERCISE VII : Rewrite the following sentences using If clauses.
Model :
a/ My brother will have enough money He will buy a bicycle If my brother has enough money, he will buy a bicycle b/ She can’t speak English She won’t apply for the job If she could speak English she would apply for the job c/ He wasn’t here He didn’t have a lot of fun.
If he had been here, he would have had a lot of fun.
1/ She can’t be employed because she doesn’t have a college degree.