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 mệnh
đề 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 ĐƯC (probable condition)
1/ Ý nghóa : 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 nghóa : Loại điều kiện này diễn tả một điều kiện khó có thể xảy ra hay

- 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), as
long 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 with
pleasure.
* Hai tiếng có nghóa phủ đònh : 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.)
2
- 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).
- ____________________________________________________
- ____________________________________________________
- ____________________________________________________
3/ If I (see) her, I (tell) her.
- ____________________________________________________
- ____________________________________________________

11/ We (go) out unless it (stop) snowing.
- ____________________________________________________
- ____________________________________________________
- ____________________________________________________
EXERCISE 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.
4
8/ 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.

4/ Unless we had enough rain, we couldn’t grow rice.
-____________________________________________________________
5/ The fishermen couldn’t have caught a lot of fish unless they had had good
nets.
-____________________________________________________________
6/ I wouldn’t buy it unless I could afford it.
-____________________________________________________________
7/ I would refuse to go unless they paid my expenses.
-____________________________________________________________
8/ I don’t agree with his economic policy. I wouldn’t vote for him unless he
changed it.
-____________________________________________________________
9/ He wouldn’t have written unless he had heard news.
-____________________________________________________________
10/ You might not have a terrible toothache unless you went to the dentist
regularly.
-____________________________________________________________
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)

1/ She can’t be employed because she doesn’t have a college degree.
→ ______________________________________________
2/ I don’t have enough money. I can’t go on a long holiday this year.
→ ______________________________________________
3/ He is very slow, so we won’t give his such an important task.
→ ______________________________________________
4/ I’ll have to work this Sunday, so I shan’t join your picnic.
→ ______________________________________________
5/ He works overtime to get more money because he has to pay father’s debt.
→ ______________________________________________
6/ City life isn’t enjoyable because everything is very expensive.
7
→ ______________________________________________
7/ There are industrial factories inside the city, that’s why pollution can’t be
reduced.
→ ______________________________________________
8/ Everything on the earth grows well because the sun always shines.
→ ______________________________________________
9/ There is a grammar error in this English composition, that’s why it can’t get
a full mark.
→ ______________________________________________
10/ I don’t have a typewriter. I can’t type it myself.
→ ______________________________________________
11/ I’ll buy a new hat. I’ll give it to you.
→ ______________________________________________
12/ You’ll ask the teacher. He’ll explain the lesson to you.
→ ______________________________________________
13/ Mary doesn’t see the sight. She can’t tell you about that.
→ ______________________________________________
14/ I don’t know his address. I can’t give it to you.