Here you are some information related to modal verbs.
1) MUST
- Obligation: I really must stop smoking (I want to give up smoking)
- Logical deduction: They must be at home (The lights are on)
2) HAVE TO
- External obligation: I have to keep speed under 110 kph (The Government tells me to keep speed under control)
We use HAS TO with third person singular! He has to wear glasses.
3) MUSTN´T
- Prohibition: You mustn´t smoke in public places
4) DON´T HAVE TO / DOESN´T HAVE TO
- Not necessary: You don´t have to bring anything to the party.
5) NEEDN´T
- Not necessary: You needn´t send me an e-mail. ( I will call you instead)
6) DON´T NEED TO / DOESN´T NEED TO
- Not necessary: You don´t need to get me anything.
7) MAY/MIGHT
- Possibility: It might/may rain tomorrow
- May can be used in formal style to request for permission: May I go to the toilet, please?
8) CAN
- Ask and giving permission: Can I go to the concert tomorrow? Yes, you can.
- Ability: I can play the piano
9) COULD
- Ask permission (more polite) : Could I borrow your pen for a minute?
- Ability in the past: When I was a child, I could read without glasses.
10) CAN´T
- Prohibition: You can´t go in there. (It says "No entry!")
- Logical deduction: He is my friend. What you are saying can´t be true.
11) SHOULD / OUGHT TO
- Advice: You should eat vegetables
Ought to is more polite
MODAL PERFECTS
Modal perfects make reference to something that happened or should have happened in the past.
Example: I should have heard my parents. (now, I regret not hearing them)
CHARACTERISTICS OF MODAL VERBS
1. They are always followed by the base form of the verb: I might play tennis tomorrow
2. They do not take -s in the third person singular present: She might play tennis tomorrow
3. They do not take DO or DID to form negatives. Negatives are formed by putting not inmmediately after the modal verb. Exception: ought to.... ought not to
4. They do not take DO or DID to form questions.
5. Modal verbs cannot be followed by another modal verb in a sentence.
Exercises
1. Choose the correct modals
- I can´t / mustn´t hear you. It´s too noisy.
- You should / might wear that colour more often. It really suits you.
- We mustn´t / don´t have to wake up early tomorrow. It´s a holiday.
- Could / Should you close the window? It´s cold in the room.
- It can / might rain tomorrow so take an umbrella.
- There´s someone at the door.It can / must be the postman.
- Don´t worry, you don´t have to/ mustn´t pay now.
- Jones could/ must be president if Smith has to resign.
- Sorry, I can´t stay any longer. I have to/might go.
- It was 5 o´clock an hour ago. Your watch can´t/ mustn´t be right.
- It´s a school rule, all the pupils have to / must wear a uniform.
- I suppose that our team must/ should win, but I´m not sure.
- Let´s tell Diana. She could not/ might not know.
-In my opinion, the government might/ should do something about this.
2. Choose the correct modal perfects.
- I´m not sure but I must have / might have left my coat in the classroom.
- You shouldn´t have / couldn´t have eaten so many sweets. That´s why you feel so ill.
- He could have / may have come to the party but he preferred to stay at home.
- Anne must have / should have forgotten about our meeting. It´s typical of her.
- We should have / shouldn´t have cooked so much. Everyone´s already eaten.
3. Write the following sentences using the modal perfect.
- They might sell their car.
They might have sold their car
- It could be Thelma on the phone.
- You shouldn´t use my computer.
- She must be tired.
- This should be taken away.
- They may come later.
4. Complete the sentences with the correct modal perfect form of the verb in brackets.
He´s not home. I think he _________ (go) out with friends.
I _______ (call), but I didn´t want to wake you up.
Everyone looks shocked; something very bad __________ (happen)
I´m angry. You __________ (take) my book without my permission.
5. Complete the sentences with the correct form of the verb in brackets. Use a modal or modal perfect.
I passed my driving test so now I ______________ (can/drive)
In my opinion, she _________ (should not/wear) jeans to the wedding last week.
I _______ (could/take) the bus, but I preferred to walk.
This area is for non-smokers so you ___________ (must not/smoke) here.
She ___________ (must/move). Nobody has seen her in ages.
I think I ____________ (might/leave) my jacket at your house yesterday.
6. Rewrite the following sentences using modals. Do not change the meaning of the original sentences. There may be more than one correct answer.
-If you want my advice, get a good lawyer!
You should/ought to get a good lawyer.
A university degree isn´t necessary for that job.
You ......................................
Perhaps my father will pick you up.
My father ............................
It isn´t necessary to make an appointment at the hairdresser´s.
You ..............................
She hasn´t phoned. Perhaps she is abroad.
I suggest you go and see a doctor.
You...................
