Expressing Certainty and Uncertainty (Present and Past)

CERTAINTY AND UNCERTAINTY (POSSIBILITY) 
PRESENT TIME
 May/Might: There is little difference between them, although MIGHT seems less possible  
                       She might come tonight (Maybe she will come)
Questions: only MIGHT (formal)
Negatives: they must be written in full: He may /might not be at home
Could: 
He could still be at home
Could he still be at home?
He couldn’t be at home.     
Must and Can’t: They are opposites 
He must be at home. (He’s certain to be at home. It also implies a deduction)
He can’t be at home. (I don’t think he is at home. I’m sure he’s not at  home)
PAST TIME
May have and Might have: these both refer to events in the past which are uncertain:
You may have left it on the bus
He might not have gone there ( It  suggests a slight possibility)
Questions are not possible.
Could have: 
It could have been him I suppose.
Could it have been him?
Must have and Can’t have: These also express certainty, but as a deduction (an opinion of what it probably happened)
The butler must have done it (I think that’s what happened) 
You can’t have seen him yesterday, he’s in Australia  (this is my proof that it is impossible)

Exercise. Rewrite the sentences using a modal verb.
1.- Maybe Janet invited him here tonight. Janet...
2.- I’m sure she is quite angry. She...
3.- Perhaps he visited us, but we were away. He...
4.-He hasn’t contacted me. He clearly thought I was unsuitable for the job.  He...
5.- I'm sure she doesn't like onions. She...  

 Solutions 

Expressing Suggestions

SUGGESTIONS:
COULD: to suggest doing something: We could go to the cinema on Friday.
SHALL WE: to suggest doing something with somebody else: Shall we sing?
SHALL I: to suggest doing something yourself. Shall I sing? (also to express offers)
MIGHT: very polite: You might want to try another shop.
WHAT ABOUT/HOW ABOUT going to Peter’s?
LET’S go outside
WHY DON’T I/WE/YOU give them what they want?

Expressing Instructions and Requests

INSTRUCTIONS AND REQUESTS: CAN, COULD, WILL, WOULD
Make coffee (please)
Make coffee, will you?
Can you make coffee?
Will you make coffee?
Would you make coffee?
Could you make coffee? (very formal)
I’d like to ask you a question. 
Would you mind helping me? 
Do you think you could help me?

Practice. Rewrite the sentences.

1. Will you help this lady with her bags? Do you mind.....                    
2. Stand up. I wonder if....                                                  
3. Play it again. Do you think.....                                           

Solutions:

Expressing Permission

PERMISSION 
CAN, COULD, MAY, are all used in asking permission:  
Can I use the phone?
Could I borrow your car? (polite)
May I come in? (more formal)
Might I speak to you? (very polite- old-fashioned.  
Use only can/can't when giving or denying premission. 
Could I stay out late tonight? No, you can't.  
BE ALLOWED TO  It’s used when talking about permission, but not when you are asking for it or giving it.  
You are not allowed to use calculators in exams.
It was only after several months that I was allowed to visit her
They have not been allowed to come.
 
Practice: Rewrite the sentences:

1. Do you mind if I sit down?                                              
2. I’d like to go to the concert, please.                                           
3. I’d like to speak next. Is it all right if......                       
4. It’s all right to have visitors after three o’clock (ALLOWED)
5. I’ll let you use my pen until I need it.                               

Solutions:

Expressing Ability

ABILITY : CAN, COULD, BE ABLE TO
1.- Present ability
                         Can, can’t: I can swim (I know how to swim)  I can lift it  ( I am able to lift it)
2.- Future ability
                          Can : I can come tomorrow (future reference)
                           Be able to : he will be able to come next week
3.- Past ability
                          Could, couldn’t: When I was ten, I could swim 
                          could vs be able to
He was a good swimmer, and could save people’s lives (we don’t  know)  
He was a good swimmer, and was able to save people’s lives (he actually did it)
                          could have
He was a good swimmer and could have saved people’s lives ( he didn’t use his ability)

Practice: Complete the sentences:
a.- There was a woman with a big hat in front of me. I ____________see a thing.
b.- I’m sorry you are in my light. I __________see what I’m doing.
c.- He had a strange ability: he _______________ move his ears really fast.
d.- She _____________ done it, but she left without trying.  
e.- When he was young he____________ run a marathon once, but he________ now.


Solutions:

Michael Jackson - Earth song - lyrics

Earth Day. April 22

Useful expressions

Could you.......? Do you mind....? Can I.....? Shall we.....? Why don't we....? 
 I agree with you 100 percent / I couldn't agree with you more / That's so true / That's for sure /
You're absolutely right./Absolutely / That's exactly how I feel/ Exactly / No doubt about it.