English Grammar - Modal Verbs

Modals Verbs

The verbs can, could, may, might, will, would, shall, should, must and ought are called modal verbs or modals. They are used before ordinary verbs and express meanings such as talking about ability, asking permissions, possibility, making requests, giving suggestions, certainty and necessity etc. Need and dare can sometimes be used like modal verbs.

Modals are often included in the group of auxiliaries. In some grammars they are called "modal auxiliaries".
The modals can, could, may, might, shall, should, will, would, must and ought are termed Defective Verbs, because some parts are wanting in them. They have no 's' in the third person singular. They have no infinitive and 'ing' forms.

Using Modals Verbs

Can - Ability, Request, Permission
Could - Past possibility, Future possibility, Suggestion
May - Permission, Future possibility, Uncertainity
Might - Permission, Polite request, Future possibility
Shall - Offer / Advice, Suggestion, Question (I & We)
Should - Advice, Suggestion, Order / instruction
Will - Future, Willingness, Make promises / offer / request
Must - Obligation, Necesity, Future possibility

CAN, MAY, COULD, MIGHT

CAN AND MAY

For Ability Or Capacity And Permission
CAN:
1. Usually expresses ability or capacity
We use can to talk about someone's skill or general abilities at a given time in the present or future.
Example:

1. He can swim like a fish.
2. They can't speak Punjabi very well.
3. You can get good marks in the exams.
4. I can swim across the river.
5. He can work this sum.
6. Can you lift this box ?

2. For Permission
a) We also use can to ask for permission to do something:
Example:

1. Can I borrow your pencil, please?
2. Can we go home now?

b) We use can to give permission:
Example:

1. You can go home now if you like.
2. You can borrow my pencil if you like.

MAY:
1. For Permission
a) Another more formal and polite way of asking for permission is with the use of may.
Example:

1. May I borrow your pencil, please?
2. May we go home now?

b) We can also use may as a more formal and polite way of giving permission:
Example:
You may go home now, if you like.

2. Wish
In very formal English; may is used to express a wish; as,
Example:

1. May you live happily and long!
2. May success attend you !

Difference between MAY and CAN

• Can and May are used to express permission. May is rather formal.
  Example:
  i) You can / may go now.
  ii) Can / May I borrow your umbrella?
  
  
• MAY is used to express possibility in affirmative sentences. CAN is used in the corresponding interrogative and negative sentences.
  Example:
  i) It may rain tomorrow.
  ii) He may be at home.
  iii) Can this be true?
  iv) It cannot be true.
  
  
• Compare 'It cannot be true' with 'It may not be true'.
  Cannot denotes impossibility,
  while may not denotes improbability.

COULD AND MIGHT

Note: Could and might are used as the past equivalents of can and may and show possibility
Example:

1. I could swim across the river when I was young. (Ability)
2. He said I might/could go. (Permission).
3. I thought he might be at home. (Possibility)
4. She wondered whether it could be true. (Possibility)

COULD:
1. We use could to talk about past time:
Example:

1. She could speak several languages.
2. They couldn't write very well.

2. Ability
Could expresses only ability to do an act, but not the performance of an act.
We should use was/were able to for ability +action in the past.
Example:

1. When the boat was upset, we were able to (or managed to) swim to the bank.
   (wrong : we could swim to the bank)

3. Permission
The use of could is more formal and polite than can:
Example:

1. Could I borrow your pencil, please?
2. Could we go home now?

4. In negative statements, however, either could or was/were able to may be used.
Example:

1. I couldn't (or: wasn't able to) solve the puzzle. It was too difficult.

MIGHT
1. Might is also used to express a degree of dissatisfaction or reproach
Example:

1. You might pay a little more attention to your appearance.

Comparison of Could, Might with Can and May

In present-time contexts could and might are used as less positive versions of can and may
Example:

1. I could attend the party.
   (Less positive and more hesitant than can attend the party)
2. Might/Could I borrow your bicycle ?
   (A diffident way of saying 'May/Can I ......... ')
3. It might rain tomorrow.
   (Less positive than 'It may rain ')
4. Could you pass me the salt ?
   (Polite request)

Note: the use of can, could, may and might with the perfect infinitive:
Example:

1. He is not there. Where can he have gone?
   (= Where is it possible that he has gone? - May express annoyance.)
2. You could have accepted the offer.
   (= Why didn't you accept the Offer?)
3. Fatima may/might have gone with Sara.
   (= Possibly Fatima has gone/ went with Sara.)
4. Why did you drive so carelessly? You might have run into the lamppost.
   (= It is fortunate that you didn't run into the lamppost.)

SHALL, SHOULD, WILL WOULD

SHALL AND WILL
Shall is used in the first person (I) and will in all persons (we, you, he, she, it,they .... etc) to express pure future.
Note: I/we shall is less common than I/we will
Example:

1. I shall/will be twenty-five next birthday.
2. We will need the money on 15^th.
3. When shall we see you again?
4. Tomorrow will be Sunday.
5. You will see that I am right.

SHALL
A) For Command, Promise Or Threat
Shall is sometimes used in the second and third persons to express a command, a promise, or threat
Example:

1. He shall not enter my house again. (Command)
2. You shall have a holiday tomorrow. (Promise)
3. You Shall be punished for this. (Threat)

Note: These uses of shall are formal and generally avoided in modern English.

B) For Asking A Will
Questions with shall I/we are used to ask the will of the person addressed
Example:

1. Shall I open the door ? (i.e, Do you want me to open it ?)
2. Which pen shall I buy ? (i. e, What is your advice ?)
3. Where shall we go ? (What is your suggestion ?)

WILL
Will is used to express
(1) Purpose (Volition or Will):
Example:

1. I will (= am willing to) carry your books.
2. I will (= promise to) try to do better next time.
3. I will (=am determined to) succeed or die in the attempt. (show strong-stressed.

(2) Characteristic habit
Example:

1. He will talk about nothing but films.
2. She will sit for hours listening to the wireless.

(3) Assumption or probability
Example

1. This will be the book you want, I suppose.
2. That will be the postman, I think.

(4) Will you ? indicates an invitation or a request
Example:

1. Will you have tea ?
2. Will you lend me your scooter ?

(5) Expectation
Example:

1. He will write the report.

SHOULD AND WOULD
1. Should and would are used as the past equivalents of shall and will
Example:

1. I expected that I should (more often : would) get a first class.
2. He said he would be twenty-five next birthday.
3. She said she would carry my books.
4. She would sit for hours listening to the wireless. (Past habit)

2. Should and would are also used as

1. I should (or would) like you to help her. ('should / would like' is a polite form of 'want').
2. Would you lend me your scooter, please ? (Would you ?' is more polite than Will you ?')
3. You should have been more careful. (Should+ perfect infinitive indicates a past obligation that was not fulfilled).
4. He should be in the library now. (Expresses probability)
5. I wish you would not chatter so much. (would after wish expresses a strong desire).

SHOULD
A) For Duty Or Obligation 
Should is used in all persons to express duty or obligation
Example:

1. We should obey the laws.
2. You should keep your promise.
3. Children should obey their parents.

B) In Conditional Sentences
In condition sentences, should is used (in 'if-clause') to express a supposition that may not be true.
Example:

1. If it should rain, they will not come.
2. If he should see me here, he will be annoyed.

MUST, OUGHT TO

MUST
Must is used:
1) For Necessity Or Obligation:
Must is used to express necessity or obligation.
Example:

1. You must improve your spelling.
2. We must get up early.

2) In Tenses:
Must refers to the present or the near future. To talk about the_past - we use had to (the past form of have to); must has no past form.
Example:

1. Yesterday we had to get up early.

3) Compare Must and Have to in Obligation
Must is often used when the obligation comes from the speaker. When the obligation comes from somewhere else, have to is often used.
Example:

1. I must be on a diet. (It is my own idea.)
2. I have to be on a diet. (The doctor has told me to be on a diet.)

4) Logical Certainty:
Must can also express logical certainty.
Example:

1. Living in such crowded conditions must be difficult. (= I am sure it is difficult.)
2. She must have left already. (I am sure she has left already).

OUGHT (TO)
Ought (to) expresses:
1) Moral obligation or desirability
Example:

1. We ought to love our neighbours.
2. We ought to help him.
3. You ought to know better.

2) Probability:
Ought (to) can also be used to express probability.
Example:

1. Prices ought to come down soon.
2. This book ought to be very useful.

USED (TO), NEED, DARE

USED (TO)
1) Discontinued habit:
The auxiliary used (to) expresses a discontinued habit.
Example:

1. I used to drink coffee every morning but now I drink tea.
2. I used to live there when I was a boy.

Note: used (to) is an auxiliary verb. However, Did you use to' and `did not use to' usually replace `Used to' and 'Used not to'.

NEED
1) Necessity Or Obligation
The auxiliary need, denoting necessity or obligation.
It can be conjugated with or without do. When conjugated without do, it has no s, and -ed forms.
It is used with an infinitive without to only in negative and interrogative sentences and in sentences that contain semi-negative words like 'scarcely' and 'hardly'.
Example:

1. He need not go. (= It is not necessary for him to go)
2. Need I write to him ?
3. I need hardly take his help.

2) As Need to
When conjugated with do, need has the usual forms needs, needed and is used with a to-infinitive. It is commonly used in negatives and questions ; it sometimes occurs in the affirmative also.
Example:

1. Do you need to go now ?
2. I don't need to meet him.
3. One needs to be careful.

Compare: Need (to) and Need

Example:
 (i) I didn't need to buy it. (= It was not necessary for me to buy it and I didn't buy it.)
(ii) I needn't have bought it. (=It was not necessary for me to buy it, but I bought it).

DARE
The auxiliary dare (= be brave enough to), as distinct from the ordinary verb dare (= challenge), does not take -s in the third person singular present tense. It is generally used in negative and interrogative sentences.
When conjugated without do, it is followed by an infinitive without to, when conjugated with do, it takes an infinitive with or without to; after it.
Example:

1. He dare not take such a step.
2. How dare you contradict me?
3. He dared not do it.
4. He doesn't dare speak to me.

POINTS TO REMEMBER

Here are three noteworthy points related to Modals helping verbs.
Point 1:

• Don't write "could of," "should of," or "would of." It's a serious writing mistake.
• "Could've" is a contraction of "could have," "should've" is a contraction of "should have," and "would've" is a contraction of "would have."

Point 2:

• Expand "can't" to "cannot" not "can not."
• "Cannot" (one word) is the most common expansion of the contraction "can't."

Example:

• You cannot open a book without learning something.
• Do not let what you cannot do interfere with what you can do.

(Expanding "can't" to two words is considered more emphatic.)

(Point 3):
1. Use "can" for ability and "may" for permission.
2. "Can" is a modal auxiliary verb meaning "to be able to." "May" is a modal auxiliary verb meaning "to be permitted to."
Example:

• She can do the splits.
  (She has the ability to do the splits.)
• May I have a quick word with the students?
  (Am I permitted to have a quick word with the students?)
• "Can I play outside, grandma?"
• "You can, dear. You're just not allowed."

Nowadays, "can" is often used for permission, especially in an informal setting.
Example:

• Can I have a biscuit, grandma?
• "You can, dear. You're just not allowed one."

REVIEW OF MODAL VERBS

Present tense	Past tense
Will.	Would (Used to)
Shall	Should (Ought to) (had better)
Can	Could
May	might
Must	had to

1. Negation Of Modals:
add 'not' after the modal.
Example:

• John would like to leave.
• John would not like to leave.

2. Question With Modals:
Place the modal at the beginning of sentence.
Example:
Would John like to leave?

3. Modal verbs Follow by simple verb forms:
There can never be gerund, verb +s, past tense or infinitive.

4. Two ways Modal verbs can occur:

• Modal + Simple form of the verb
  e.g. would be, could go, will have
  
  
• Modal + have + Verb (in past participle)
  e.g. would have been, could have been, will have been