- Điều gì đó có thể xảy ra ở hiện tại, tương lai nhưng không chắc chắn The phone is ringing.. It could be Tim..[r]
(1)ÔN LUYỆN CÁC CHỦ ĐIỀM NGỮ PHÁP CHO KỲ THI THPTQG CHỦ ĐIỀM 4: ĐỘNG TỪ KHUYẾT KHUYẾT
(MODAL VERBS) I/ Definition ( Định nghĩa ):
- Động từ khuyết khuyết động từ đặc biệt , chúng khơng có đầy đủ tất thân chúng với chủ ngữ tạo câu hồn chỉnh mà cần phải có động từ (trừ số trường hợp ngoại lệ) theo sau
- Động từ khiếm khuyết tất gồm có: SHALL, WILL, WOULD, CAN, COULD, MAY, MIGHT, SHOULD, MUST, OUGHT TO
II/ Modal Verbs: 1 Can
Khẳng định: can + V(bare) (có thể) Phủ định: can’t + V(bare) (không thể)
* Diễn tả:
- Khả tại, tương lai Ex: They can speak English
- Sự xin phép cho phép Can’t dùng để từ chối lời xin phép Ex: Can I use your phone? Yes, of course you can / No, I’m afraid you can’t
- Lời yêu cầu, đề nghị gợi ý Ex: Can I carry your bag?
- Can’t: nói chắn điều xảy Ex: She has cleaned the floor It can’t be dirty
2 Could
Khẳng định: could + V(bare) Phủ định: couldn’t + V(bare) *Diễn tả:
- Khả (phổ quát, chung chung) khứ Ex: I could swim when I was ten
(2)- Sự xin phép Could lễ phép trịnh trọng can không dùng couldn’t phép từ chối lời xin phép
CouldI ask you something? Yes, of course you can Couldwe picnic here? I’m afraid you can’t
3 May / might * Diễn tả
- Điều xảy (không chắn)
HIỆN TẠI QUÁ KHỨ
Khẳng định Phủ định
may / might + V(bare) may / might + not + V(bare)
may / might have + V3/-ed may / might + not + have + V3/-ed
Ex: He may / might be in his office (= perhaps he is in his office) A: I can’t find my bag anywhere
B: You may / might have left it in the shop (= perhaps you left it in the shop) - Yêu cầu lịch xin phép hay cho phép
Ex: May I use your phone? – Yes, you may / Sorry, you may not - Lời chúc hay diễn tả niềm hy vọng
Ex: May you be happy
Note: Could dùng thay cho may / might
Ex: The phone is ringing It could be Tim (= it may / might be Tim)
4 Must / mustn’t
a must + V(bare) (phải),
* Diễn tả:- bắt buộc cần thiết (có tính chủ quan) Ex: My car is very dirty I must wash it now
- suy luận hợp lý chắn Ex: John’s lights are out He must be sleep
(3)- lời khuyên lời yêu cầu nhấn mạnh You must be here before eight o’clock tomorrow
b mustn’t + V(bare) (không được) diễn tả cấm đoán Ex: You must keep it in a secret You mustn’t tell anybody else
5 Needn’t + V(bare) = don’t / doesn’t have to + V(bare) : không cần, không cần phải Needn’t + V(bare) # must + V(bare)
Ex:We have got plenty of time We needn’t hurry ( = we don’t need to hurry = we don’t have to hurry)
6 Sự khác must have to
* must: + cần thiết hay bắt buộc có tính chủ quan (người nói đưa ý tưởng riêng mình) + khơng thể dùng tương ai, tiếp diễn, khứ,
Ex: I must study for the exam
I haven’t phoned Ann for ages I must phone her tonight
* have to: + cần thiết hay bắt buộc có tính khách quan (sự bắt buộc điều kiện bên ngoài: nội qui, qui định, luật pháp, …)
+ dùng thay cho must trường hợp dùng must Ex: You can’t turn right here You have to turn left
I had to go to hospital
7 Should
Khẳng định: should + V(bare) (phải, nên) Phủ định: shouldn’t + V(bare) (không nên) * Diễn tả:
- bắt buộc bổn phận (nghĩa không mạnh must) Ex: You shouldn’t drink and drive
- lời khuyên ý kiến Ex: You should stop smoking
(4)* Diễn tả:
- bắt buộc bổn phận (tương tự should) - lời khuyên kiến nghị
Ex: You are not very well Perhaps you ought to see a doctor
9 Had better + V(bare) (nên, tốt hơn) / had better not + V(bare) (không nên) - dùng đưa lời khuyên
Ex: It’s cold The children had better wear their coats
You don’t look very well You’d better not go to work today
10 used to + V(bare) : +: S + used to + V(bare) …
-: S + didn’t use to + V(bare) … ?: Did + S + use to + V(bare) …?
Ex: I didn’t use to like her but we are best friends now
- be used to + V-ing / noun: quen, quen với Ex: I am used to living alone
- get used to + V-ing / noun: trở nên quen với Ex:You’ll soon get used to living in the country
* Note:
- Can’t / couldn’t have + V3/-ed: diễn tả điều gì chắn khơng xảy khứ Ex: Mary can’t / couldn’t have caught the bus It doesn’t run on Sundays
- Must have + V3/-ed: diễn tả điều chắn xảy khứ Ex: The phone rang but noone answered it They must have been asleep
(5)
* Exercise: Choose the modal verb to complete the blank in each of the following sentences: Where’s Mary? She ………… be here by now
A could B might C must D will “Write to me when you get home.” “I ……… .”
A must B should C will D can Mr Brown is very rich He ………… work hard for a living
A mustn’t B shouldn’t C can’t D doesn’t have to
These are my most precious possessions so you ………… touch them, but you ……… look at them A can’t/ must B mustn’t/ can C shouldn’t/ must D mustn’t/ should
I ………… speak Arabic fluently when I was a child
A could B can C would D should
You ……… forget to pay the rent tomorrow The landlord is very strict about paying on time A mustn’t B don’t have to C couldn’t D won’t
You ………… avoid walking under a ladder
A can B will C should D must
I’m certain that Tim has gone home His jacket’s not here He ……… gone home A could have B might have C should have D must have ………… this new product prolong human life?
A May B Should C Can D Might 10 Why are you so late? You ……… here two hours ago!
A need have been B must have been C should have been D ought to have been 11 Yesterday I …… cram all day for my French final I didn’t get to sleep until after midnight A had to B should C must D could
12 She hasn’t eaten anything since yesterday She ……… be really hungry A might B will C must D can 13 I don’t know who rang, but it ………… Jim
A could have been B should have been C might have been D.shouldn’t have been 14 It ………… rain this evening Why don’t you take an umbrella?
A could be B must C might D had better 15 If you’ve worried about your health, perhaps you ………… see a doctor
(6)ĐÁP ÁN