CHUYÊN ĐỀ: CÂU ĐIỀU KIỆN

Ex: If I have money, I will buy this house. Please call me if you hear anything from Jane. If I were you, I would buy this house. If he had studied harder for this test, he would have passed it Note: Mệnh đề điều kiện có thể đứng trước hoặc đứng sau mệnh đề chính. Có thể dùng các từ sau thay thế cho If trong câu điều kiện: Provided (that), On condition (that), As long as = so long as (miễn là, với điều kiện là), Suppose = Supposing (giả sử như), In case (trong trường hợp), Even if (ngay cả khi, dù cho)…

BÁO CÁO CHUYÊN ĐỀ BỒI DƯỠNG ÔN THI THPT QG

TÊN CHUYÊN ĐỀ: CÂU ĐIỀU KIỆN

HỆ THỐNG KIẾN THỨC VỀ CHUYÊN ĐỀ CÂU ĐIỀU KIỆN

A CONDITIONAL SENTENCES

I Structures and uses of conditional sentences

1 thể hiện hành động có thể

có thật ở hiện tại hoặc tương

lai

If + S1 + V1 (simple present)

S2+ will / can / may + V2 (inf.)

2 thể hiện hành động không

có thật ở hiện tại

If + S1 + V1 (past simple) (be: were)

S2 + would / could/ might + V2 (inf.)

3 thể hiện hành động không

có thật ở quá khứ

If + S1 + had + V1 (PII) S2 + would / could / might + have + V2

(PII) Ex: If I have money, I will buy this house

Please call me if you hear anything from Jane

If I were you, I would buy this house

If he had studied harder for this test, he would have passed it

* Note:

- Mệnh đề điều kiện có thể đứng trước hoặc đứng sau mệnh đề chính.

- Có thể dùng các từ sau thay thế cho If trong câu điều kiện: Provided (that), On condition (that),

As long as = so long as (miễn là, với điều kiện là), Suppose = Supposing (giả sử như), In case (trong trường hợp), Even if (ngay cả khi, dù cho)…

II Some variations of conditional sentences

1 Variations of conditinal sentence type 1

1 diễn tả 1 sự thật, 1 quy luật,

1 thói quen

If + S1 + V1 (simple present) S2 + V2 (simple present)

3 diễn tả lời gợi ý, khuyên

răn, đề nghị hoặc yêu cầu

nhưng nhấn mạnh về hành

động

S2 + would like to/must/have to/should + V(inf.)

4 có thể xảy ra trong tương

lai và nhấn mạnh trạng thái

diễn ra/hoàn thành của sự việc

S2 + V2 (future continuous/ future perfect)

5 diễn tả lời đề nghị, gợi ý,

bày tỏ ý kiến mang tính lịch

sự

If + S1 + can/may/must/have to/should/be going to + V(inf.)

S2 + V2 (simple future)

6 không chắc về thời gian

của điều kiện có thật mà nhấn

mạnh tính hoàn tất của nó

If + S1 + V1 (present perfect)

7 diễn tả hành động đang xảy

ra ngay trong hiện tại

If + S1 + V1 (present continuous)

Ex: - If you want to lose weight, you should do some exercise

- If you eat this poisonous fruit, you die at once

- If we leave Hanoi for Hue today, we shall be staying in Hue tomorrow

- If you are hungry, go to a restaurant

2 Variations of conditinal sentence type 2

1 If + S1 + V1 (past simple) S2 + would/should/could/might/had to/ought to +

be V-ing

2 If + S1 + V1 (past continuous) S2 + would/could + V2 (inf.)

3 If + S1 + V1 (past perfect)

Ex: - If we left Hanoi for Hue this morning, we would be staying in Hue tomorrow

- If we were studying English in London now, we could speak English much better

- If you had taken my advice, you would be a millionaire now

3 Variations of conditinal sentence type 3

1 If + S1 + V1 (past perfect) S2 + would/could/might + have + been

V2(ing)

S2 + would/could + V2 (inf.)

2 If + S1 + V1 (past perfect continuous) S2 + would/could/might + have + V2 (PII)

Ex: - If you had left Hanoi for Haiphong last Saturday, you would have been swimming in Doson last Sunday

- If she had followedmy advice, she would be richer now

- If it hadn't been raining the whole week, I would have finished the laundry

Note: Một số các từ chỉ điều kiện

- even if + negative verb (cho dù )

Ex: You must go tomorrow even if you aren’t ready

Whether or not + positive verb (dù có hay không)

Ex: He likes watching TV whether or not the show is god

unless + positive verb = if not (trừ phi, nếu không)

Ex: If you don’t start at once, you will be late = You will be late unless you start at once

But for that + unreal condition (nếu không thì )

Ex; Her father pays her fees, but for that she wouldn’t be here ( but she is here)

present điều kiện k thực ở hiện tại

My car broke down, but for that I could have come in time

past simple điều kiện k thực ở quá khứ

otherwise + conditional sentence ( kẻo, nếu không thì )

- điều kiện có thể thực hiện: We must be back before midnight, otherwise I will be locked out

- điều kiện không thể thực hiện: Her father pays her fees, otherwise she couldn’t be here

present điều kiện k thực ở hiện tại

I used a computer, otherwise it would have taken longer

quá khứ Điều kiện không thực ở quá khứ

Trong tiếng Anh hàng ngày, người ta dùng or else để thay thế cho otherwise.

Provided / providing (that) / on condition that / as long as / so long as ( với điều

kiện là, miễn là)

Ex: You can camp here provided (that) you leave no mess

Suppose/ supposing? = what if ? (giả sử vì sao, nếu vì sao)

Ex: Suppose the plane is late? = what will happen if the plane is late?

- Từ nối này còn được sử dụng để gợi ý: Suppose you ask him = why don’t you ask him?

What if I’m- tao thế thì sao nào (đưa ra sự thách thức)

If only + simple present = hope that

Ex: If only he comes in time

If only he will head your advice

If only + simple past = wish that

Giá mà, trái với thực tế If only he didn’t smoke (but he doesn’t)

If only she had come in time (but she didn’t)

if only + would verb - ước sao, mong sao

- dùng để diễn đạt một ước muốn ở hiện tại hoặc ước muốn về tương lai

Ex: If only he would drive more slowly (but he drives so fast)

If only it would stop raining

III Inversion in conditional sentences

1 Type 1: Đảo “Should” lên đầu câu thay cho vị trí của “If”

If + S + V (present simple), main clause = Should + S + V ((inf.), main clause.

Ex: If anybody phones me, please tell them I’m busy

 Should anybody phone me, please tell them I’m busy

Điều kiện loại 1 có sử dụng thời hiện tại hoàn thành, lấy “should” thay “If” sao đó để nguyên thể hoàn thành với “have done” ở tất cả các ngôi

If + S + V (present perfect), main clause = Should + S + have + V(PII), main clause.

Ex: If she has finished the work, she can go home

=> Should she have finished the work,

2 Type 2: Đảo “Were” lên đầu câu thay cho vị trí của “If”

* Có V “to be”

If + S + were …, main clause  Were + S + …, main clause

Ex: If I were you, I wouldn’t do that

* Có V thường:

If + S + Ved …, main clause  Were + S + to V, main clause

Ex: If he worked more slowly, he wouldn’t make many mistakes

 Were he to work more slowly, he wouldn’t make many mistakes

3 Type 3 : Đảo “Had” lên đầu câu thay cho vị trí của “If”

If + S + had + V (P2) …, main clause  Had + S + V (P2) …, main clause

Ví dụ: (câu 5 bài I section B mã đề 168 đề thi THPT QG 2017)

She didn’t pass the exam because of her serious illness

 Had she not been seriously ill, she would have passed the exam.

Note: Đối với cả ba loại câu điều kiện, nếu mệnh đề IF là phủ định thì ta đặt NOT sau S.

Ex: - If you don’t believe what I said, ask your mother

 Should you not believe what I said, ask your mother

- If she were not shy, she would have a good time at the party

 Were she not shy, she would have a good time at the party.

- If I hadn’t seen it, I wouldnt have believed it

 Had I not seen it, I wouldnt have believed it

IV Some basic types of exercises

1 Dạng chia động từ: - Nếu câu điều kiện đã cho trước 1 mệnh đề, cần xét xem động từ của

mệnh đề cho sẵn thuộc loại nào, rồi xem câu đó thuộc điều kiện loại mấy, dạng cơ bản hay biến thể Như vậy, ta sẽ chọn được động từ để hoàn thiện mệnh đề còn lại

- Nếu câu điều kiện yêu câu ta chọn động từ để hoàn thành cả 2 mệnh đề thì ta phải xét ý nghĩa của câu hoặc xem có manh mối gì trước đó không để xác định loại câu điều kiện Xảy ra ở quá khứ thì chia loại 3, nếu không có dấu hiệu nào của quá khứ thì dịch nghĩa: nếu thấy không có khả năng hoặc khó có khả năng xảy ra thì dùng loại 2, nếu có khả năng xảy ra thì dùng loại 1

- Nếu câu điều kiện có sử dụng thì quá khứ hoàn thành ở mệnh đề điều kiện và mệnh đề chính có

từ “now” thì đó sẽ là loại câu điều kiện pha trộn

Ví dụ 1: (câu 21 mã đề thi 401 đề thi THPT QG 2018)

If Martin were here now, he us to solve this difficult problem

Nhìn vào ví dụ ta loại hai đáp án B và D vì ở thì hiện tại Xét thấy mệnh đề điều kiện ở thì quá khứ nên chọn A

Ví dụ 2: (câu 8 mã đề thi 424 đề thi THPT QG 2018)

If he didn’t have to work today, he his children to the zoo

Tương tự như ví dụ 1, xét thấy mệnh đề điều kiện ở thì quá khứ nên chọn B

Ví dụ 3: (câu 22 mã đề thi 401 đề thi THPT QG 2019)

We on a field trip if the weather is fine this weekend

A could have gone B will go C would go D went

Ví dụ 4: (câu 8 mã đề thi 424 đề thi THPT QG 2019)

If you follow my directions, you _ her house easily

A would find B would have found C.found D will find

Mệnh đề điều kiện ở thì hiện tại đơn nên đây là câu điều kiện loại 1, chọn đáp án D

2 Dạng viết lại câu dùng IF: Dạng này người ta sẽ cho 2 câu riêng biệt hoặc nối với nhau bằng

các chữ như: so = that’s why, because:

- Cả 2 câu đều chia thì tương lai thì dùng loại 1 (không phủ định)

- Một bên hiện tại, một bên tương lai / hiện tại thì dùng loại 2 (phủ định)

- Nếu có quá khứ trong đó thì dùng loại 3 (phủ định)

Note:

- Phủ định là câu đề có “not” thì ta dùng không có “not” và ngược lại.

- Nếu có “because” thì để if ngay vị trí because.

- Nếu có “so, that’s why” thì để if ngược với vị trí của chúng.

Ví dụ 1: I will go there I will buy you a dog.

=> If I go there, I will buy you a dog

Ví dụ 2: (câu 47 mã đề 402 đề thi THPT QG 2017)

They were late for the meeting because of the heavy snow

A If it snowed heavily, they would be late for the meeting

B Had it not snowed heavily, they would have been late for the meeting

C But for the heavy snow, they wouldn’t have been late for the meeting

D If it didn’t snow heavily, they wouldn’t be late for the meeting

Ta thấy đáp án A và D sử dụng sai loại câu điều kiện, đáp án B sai nghĩa Chọn đáp án C

Ví dụ 3: (câu 24 mã đề 403 đề thi THPT QG 2017)

He was successful in his career thanks to his parents’ support

A Had it not been for his parents’ support, he wouldn’t be successful in his career

B If his parents hadn’t supported him, he wouldn’t have been successful in his career

C But for his parents’ support, he wouldn’t be successful in his career

D Without his parent’s support, he would have been successful in his career

Ta thấy hai vế câu đã cho cùng ở quá khứ nên viết lại câu ở điều kiện loại 3, loại đáp án A và C Đáp án D sai nghĩa, chọn đáp án B

3 Dạng viết lại câu đổi từ câu có if sang dùng unless:

Học sinh cần xác định rõ Unless được sử dụng để đưa ra giả thuyết vì thế động từ theo sau chúng được chia như trong mệnh đề if của câu điều kiện, trong đó có thêm lưu ý Unless = If … not vì thế các em cần lưu ý không để bị sai nghĩa trong câu

- Nếu vế If có chứa phủ định  Unless sẽ thế vào chỗ chữ If, bỏ phủ định, giữ nguyên vế mệnh đề

chính

Ex: If you don’t speak loudly, he won’t hear

=> Unless you speak loudly, he won’t hear

- Nếu vế If không có chứa phủ định  thế Unless vào vị trí của If, đổi mệnh đề chính sang thể ngược lại

Ex: If you study hard, you will pass the exam

 Unless you study hard, you won’t pass the exam

Note:

- Vế chứa Unless luôn ở thể khẳng định

- Ta thường dùng unless trong những lời có tính chất cảnh cáo:

Ex: We’ll be late unless we hurry

Unless you work much harder, you won’t pass the exam

4 Dạng viết lại câu đổi từ câu có without sang dùng if: Dùng if… not…., bên kia giữ nguyên

(tùy theo nghĩa mà có câu cụ thể)

Vế mệnh đề chính loại 2  câu điều kiện loại 2

Vế mệnh đề chính loại 3  câu điều kiện loại 3

Ex: Without your help, I wouldn’t pass the exam

 If you didn’t help, I wouldn’t pass the exam

5 Dạng viết lại câu đổi từ câu có Or, otherwise sang dùng if :

Dạng này thường có cấu trúc là câu mệnh lệnh + or, otherwise + S will …

Cách làm như sau:If you don’t ( viết lại, bỏ or, otherwise )

Ex1: Hurry up, or you will be late

If you don’t hurry, you will be late

Ex2: Ms Phương helped me a lot, otherwise I would have failed

If Ms Phuong had not helped me, I would have failed

6 Dạng viết lại câu đổi từ câu có But for sang dùng if:

- Trong câu điều kiện loại 2: Dùng “if it weren’t for” thế cho “but for”, phần còn lại giữ nguyên

- Trong câu điều kiện loại 3: Dùng “if it hadn’t been for” thế cho “but for”, phần còn lại giữ nguyên

Ex: But for your help, I would die

If it weren’t for your help, I would die

7.Các dạng câu điều kiện ám chỉ: As long as, provided, providing (that), so long as: những thành ngữ này có nghĩa 'nếu' hay 'trong trường hợp mà'.

Cách làm : Học sinh cần xác định các từ nêu trên thường hiểu nghĩa tương đương với từ If vì thế

động từ theo sau các cụm từ này cần chia trong mệnh đề phụ

You can use my car as long as you drive carefully

You can use my car so long as you drive carefully

Travelling by car is convenient provided (that) you have somewhere to park Travelling by car is convenient providing (that) you have somewhere to park

V Các bài tập tự giải

Exercise 1: Put the verbs in correct forms using conditional sentence type 1

1 David will leave for Ren tomorrow if the weather (be) fine

2 What will you do if you (not / go) away for the weekend ?

3 The game (start) if you put a coin in the slot.

4 If you (be) scared of spiders, don’t go into the garden

5 We’ll have to go without John if he ( not arrive)……….soon

6 Please don’t disturb him if he (be) busy

7 If she (accept) your card and roses, things will be very much hopeful

8 If a holiday (fall) on a weekend, go to the beach

9 If she (come)……… late again, she’ll lose her job

10 If he (wash)……… my car, I’ll give him $20

Keys:

1 is 2 do not go 3 starts

4 are 5 does not arrive 6 is

7 accepts 8 falls

9 comes 10 washes

Exercise 2: Put the verbs in correct forms using conditional sentence type 2

1 If I knew his address, I (write) to him

2 If the sun (be) shining now, we would go to the beach

3 If you (paint)……….the walls white, the room would be much brighter

4 If he knew that it was dangerous he (not come)………

5 I (buy)……… shares in that company if I had some money

6 If you drove more carefully, you (not have)………… so many accidents

7 If I (be)……… you , I (not worry)……… about going to university

8 If I (have)………any money, I would give you some

9 Mary doesn’t study hard She (not pass)……… the examination unless she worked harder

10 The man would go abroad if he (can speak)……… japanese

Keys:

1 would write 2 were 3 painted

4 would not come 5 would buy 6 would not have

7 were/ would not worry 8 had

9 would not pass 10 could speak

Exercise 3: Put the verbs in correct forms using conditional sentence type 3

1 If Mary (wear)…………a raincoat, she would not have got a cold

2 There (not have)… …an accident if the driver in front hadn’t stopped so suddenly

3 If she had eaten something, she (not feel)……… hungry

4 If I (have)………a sound sleep last night I would have been well

5 If it (not rain)…………yesterday we would have had lunch in t he garden

6 If it had not been very expensive I (buy)……… it

7 If the teacher (speak)…………more slowly Peter would have understood the lessons

8 If I (have) my camera with me yesterday, I (take) a picture of Alex standing on his head

9 The cowboy pulled his gun to shoot at the rattlesnake, but he was too late

If he (be) quicker to pull the trigger, the snake (not-bite) him

on the foot

10 If you (be) more careful, you wouldn't have cut yourself

Keys:

1 had worn 2 would not have had

3 would not have felt 4 had had

5 had not rained 6 would have bought

7 had spoken 8 had had/ would have taken

9 had been / would not have bitten 10 had been

Exercise 4: Choose the correct answer A, B, C or D

1 If I the same problem you had as a child, I might not have succeeded in life as well

as you have

A have B would have C had had D should have

2 I you sooner had someone told me you were in the hospital

A would have visited B visited C had visited D visit

3 more help, I would call my neighbor

A needed B should I need C I have needed D I should need

4 then what I know yesterday, I would have saved myself a lot of time and trouble over the years

A had I known B did I know C If I know D If I would know

5 Do you think there would be less conflict in the world if all people _the same language?

A spoke B speak C had spoken D will speak

6 If you can give me one good reason for your acting like this, this incident again

A I will never mention B I never mention

C will I never mention D I don’t mention

7 If I had known you were asleep, I so much noise when I came in

A didn’t make B wouldn’t have made C won’t make D don’t make

8 Unless you all of my questions, I can’t do anything to help you

A answered B answer C would answer D are answering

9 Had you told me that this was going to happen, I it

A would have never believed B don’t believe C hadn’t believed D can’t believe

10 If Jake to go on the trip, would you have gone?

A doesn’t agree B didn’t agree C hadn’t agreed D wouldn’t agree

11 J: “John went to the hospital alone”,

K: “If ,I would have gone with him”

A had he told me B he had told me C he has told me D he would tell me

12 If you , I would have brought my friends over to your house yesterday to watch T.V, but I didn’t want to bother you

A had studied B-studied C hadn’t studied D didn’t study

13 Peter: “Did you need help with your Math last night?”

Mary: “If I had needed, I you”

A would call B called C would have called D will call

14 If someone in to the store, smile and say, “May I help you?”

A comes B came C come D should come

15 “Here’s my phone number”.

“Thanks I‘ll give you a call if I some help tomorrow”

A will need B need C would need D needed

16 If I didn’t work for an accounting firm, I in a bank now

A work B will work C have worked D would work

17 The death rate would decrease if hygienic conditions improved

A was B is C were D had been

18-The education in Japan if the basic principles of education had not been taken into consideration

A would go down B would have gone down

C went down D had gone down

19 If there , the rice fields could have been more productive

A had been enough water B were enough water

C would be enough water D are enough water

20 The patient will not recover unless he an operation

A had undergone B would undergo C undergoes D was undergoing

21 If she him, she would be very happy

A would meet B will meet C met D should meet

22-If he a thorough knowledge of English, he could have applied for this post

A had had B had C has D has had

23 If I had enough money, I abroad to improve my English

A will go B would go C went D should have go to 24.The bench would collapse if they on it

A stood B stand C standing D stands

25-If it convenient, let’s go out for a drink tonight,

A be B is C was D were

Keys:

1 C 2 A 3 B 4 A 5 A

6 A 7 B 8 B 9 A 10 C

11 B 12 C 13 C 14 A 15 B

16 D 17 C 18 B 19 A 20 C

21 C 22 A 23 B 24 A 25 B

Exercise 5: Give the correct form of the verbs in brackets

1 If we meet at 9:30, we (have) _plenty of time

2 If you (find) _ a skeleton in the cellar, don't mention it to anyone

3 The zookeeper would have punished her with a fine if she ( feed) _ the animals

4 If you pass your examination, we (have) _a celebration

5 Lisa would find the milk if she (look) _ for it in the fridge

6 What (happen) _if I press this button?

7 The door will be unlocked if you (press) _ the green button

8 I should have voted for her if I (have) _ a vote then

9 If you go to Paris, where you (stay) _?

10 If you (swim) _ in this lake, you'll shiver from cold

11 If someone offered to buy you one of those rings, which you (choose) _?

12 The flight may be cancelled if the fog (get) _thick

13 If the milkman (come) _, tell him to leave two pints.

14 I (call) _ the office if I were you

15 Someone (sit) _on your glasses if you leave them there

16 You would hear my explanation if you (not talk) _so much

17 What I (do) _if I hear the burglar alarm?

18 If you (read) _the instructions carefully, you wouldn't have answered the wrong question

19 If Mel (ask) _ her teacher, he'd have answered her questions

20 I would repair the roof myself if I (have) _a long ladder

21 Unless they turn that radio off, I (go) _mad

22 If you were made redundant, what you (do) _?

23 We'll have a long way to walk if we (run) _out of petrol here

24 If you shake that bottle of port, it (not be) _ fit to drink

25 If you spoke louder, your classmates (understand) _ you

26 I'll probably get lost unless he (come) _with me

27 You (not have) _ so many accidents if you drove more slowly

28 If you (wear) _ a false beard, nobody would have recognized you

29 If she (leave) _ the fish here, the cat will eat it

30 You (have) _ no trouble at school if you had done your homework

31 Unless you (tell) the truth, I won’t help you

32 You'll get pneumonia if you (not change) _ your wet clothes

33 If I had known that you couldn't eat octopus, I (not buy) _ it

34 If they (hang) _ that picture lower, people would be able to see it

35 She (be) _able to walk faster if she didn’t have such high-heel shoes

36 I (bring) _ you some beer if I had known that you were thirsty

37 If you had touched that electric cable, you (be) _ electrocuted

38 If the story hadn't been true, the newspaper (not print) _ it

39 I (not buy) _ things on the installment system if I were you

40 Dan (arrive) _ safe if he drove slowly

Keys:

1 will have 2 find 3 had fed 4 will

5 looked 6 will happen 7 press 8 had had

9 will you stay 10 swim 11 would you choose 12 gets

13 comes 14 would call 15 will sit 16 don’t talk

17 will you do 18 had read 19 had asked 20 had

21 will go 22 would you do 23 run 24 won’t be

25 would have understand 26 comes 27 wouldn’t have

28 had worn 29 leaves 30 would have had 31 Tell

32 don’t change 33 wouldn’t have bought 34 hung

35 would be 36 would have brought 37 would have been

38 wouldn’t have printed 39 wouldn’t buy 40 would drive

Exercise 6: Rewrite the following sentences using Unless

1 If he doesn't practice writing every day, he can't improve his writing skill

=> Unless

2 If you are absent from school, you have to write a sick-note