Modal verbs | Can Could May Might

Can

1. Ability or lack of ability in the present or future

. I can see you at 9pm tomorrow.Can you manage that?

. They can’t  dance

2.Giving/not giving permission

. You can use my office

. You can’t smoke here

Could

1. Ability or lack ability in the past

. I could read without glasses last year

. I couldn’t sleep last night

2. Making a request (always in the question form)

. Could you repeat that please?

. Could we have a break please ?

3.Making suggestion (only in the affirmative)

.What do you suggest we have for dinner?

.We could have fish

May 

1. Asking for permission

May I use your pen?

May we have a look?

2. Strong possibility in the present or future

It may happen again

She may not accept that offer

Might

1. A possibility in the presence or future

It might happen again (It could happen agin)

She might not accept the offer

=>may & might are more common for possibilities

=> we don’t use could in the negative for possibility

2. A possibility in the past (followed by ‘have done’)

. She might have missed her train(She could have missed her train)

. I might not have managed to convince her

=> ‘may ‘ can also be used to show a possibility in the past but is less

Common than might and could 

.He might/could /(may) have missed the train

=> however you must avoid using ‘may’ in a third conditional sentence

X => If I had studied more, I would/might/could/may/have passed my test.

Overusing ‘Can’

Request:

Informal  : Can you open the door?

 Formal    :  Could you open the door?

 Asking for permission

Informal  : Can I use the phone?

Formal.  : May I use the phone?

Suggestion

 Informal : We can meet next week

 Formal :  We could meet next week

Possibility: 

Informal. : It can happen again

Formal   : It may/might /could happen again

Gap filling exercise

Can you speak German?

Yes, I can, I could speak it fluently when we lived in Germany. Why do you ask?

I need this letter translated into German, Do you think you can do it?

Let me see ….Yes,I might be able to. It could take little time.though. And of course,I may need a dictionary too.. May I borrow yours?

Of course …Oh wait, my sister might have taken it. 

Let me go and have a look… No it is here.You can borrow it.

Oh, yes , your sister is a German teacher. 

You could have asked her

She is on holiday at the moment , and this can’t wait

I need it for tomorrow

I might not be able to do it for tomorrow, but I can do it for Wednesday

Wonderful . Could you email it to me when you have finished?

Sure

Reference: https://www.youtube.com/watch?v=SaBH_huiJSM