MODAL VERBS

 

Modal verbs are different from normal verbs:

1: They don't use an 's' for the third person singular.

2: They make questions by inversion ('she can go' becomes 'can she go?').

3: They are followed directly by the infinitive of another verb (without 'to').

Modal verbs are used to express:

 

Ø  Probability or possibility: to say how sure we are that something happened / is happening / will happen.

1: Talking about the present:

•          She must be on the bus. (I'm fairly sure this is a good guess)

•          She could be lost. (maybe)

•          She may be in the wrong room. (maybe)

•          She might come soon. (less probable than may) / past of may

•          She can't be at home. (I'm fairly sure this isn't true)

 

Ø  Ability

1: Talking about the present: can / can't (for both general and specific ability)

•       He can't drive.

•       We can come now.

2: Talking about the past:

could / couldn't (for general ability)

•       I could read when I was four.

was or were able to / couldn't (for specific ability)

•       She was able to pass the exam, even though she hadn't studied much.

•       I couldn't open the window.

3: Talking about the future:

will / won't be able to (general ability)

•       At the end of the course, you will be able to make your own website.

Ø  Permission / Requests we can use verbs such as 'can', 'could' and 'may' to ask for and give permission. We also use modal verbs to say something is not allowed.

•       Might/May I come in?                                   / May I call you later? (very polite)

•       Could I leave early today, please?             / Could I have a coke, please? (polite)

•       Can we swim in the lake?                             / Can you lend me your pencil, please? (informal)

Obligation, Prohibition and Advice

modal verb	Positive	Negative
have to / don't have to (had to: for the past)/ don't need to	obligation (possibly from outside) •       Children have to go to school. •       She has to pay a fine.	no obligation = don´t need to/ have to •       She doesn't have to work on Sundays. •       You don't need to eat anything you don't like.
must / mustn't	strong obligation (possibly based on the speaker's opinion) •       I must study today.	prohibition •       You mustn't smoke here.
should / shouldn't	advice •       You should save some money.	advice •       You shouldn't smoke so much.

Using modals of possibility, obligation or prohibition

Exercise 1: Modals of ability

Exercise 2: Modals of possibility

Exercise 3: Modals of obligation

Exercise 4: modal verbs