This document provides an overview of modal verbs including their meanings and usages. It discusses the different meanings and usages of modal verbs like can, could, should, may, might, will, would, must in terms of obligation, permission, possibility, ability, requests, assumptions and deductions. It also covers usages related to too and enough. Modal verbs do not take 's' in the third person singular and are always followed by the base form of the verb without 'to'. They come before the subject in questions and have different meanings depending on whether they are used in the present, past or future.

1. Upstream B1 Unit 5 Grammar Sheet
Prep Two
Modal Verbs
WHAT ARE MODAL VERBS? Ex: can, could, should, may, might, will, would, must
They don’t take (s) – Always followed by (inf) without (to) - Followed by (not) in negation
Come before subject in questions (without helping verbs): He must go now → Must he go now?
Usages (Meanings):
1- Obligation / Necessity/ Duty:
Present: (Must = Has to/Have to) (I have / He has to see a doctor)
Negation: Mustn’t = Doesn’t have to/Don’t have to (He doesn't have to see him/ You don’t have to see him)
Past: Must/ have to → Had to (He had to see a doctor)
Past Negation: Didn’t have to (He didn't have to see a doctor)
2- Ask for or Give Permission AND Prohibition = (not allowed):
Can/ May = allowed (May is more formal)
Can’t / Mustn’t= not allowed (Must is more powerful)
3- Possibility:
Can + inf General situations
To lose weight, you can take exercises or eat a balanced diet.
Could / May/ Might + inf Specific situations
You should study this lesson, it may be important.
In Questions: to ask about possibility:
-Do you think he could / might fix it? -Do you think it can work?
We can’t use (may) in questions to ask about possibilities.
Possibility in the past:
Could/might / would + have + pp
sth was possible in the past but didn’t happen: He might have succeeded if he studied.
4- Ability/ inability
Present: Can = (am/ is/ are) able to (I can drive = I am able to drive)
Future: will be able to (I will able to drive)
Past: Could = (was/were) able to (I could drive when I was 16= I was able to drive when I was 16)
could not = was not / were not (I could not drive when I was 16 = I was not able to drive when I was 16)
5- Requests: ex 10 p. 59

2. 6- Logical Assumptions/ Deductions
Present of all modals: must, may, can’t …etc + inf
Past of all modals: must, may, can’t … etc + have + pp
Different Meanings:
Must: sure
Present: She’s been working all day, so she must be tired now = I am sure that she is tired now.
Past: She’s been working all week, so she must have been tired yesterday = I am sure she was tired yesterday.
May/ might / could: not sure
Present: John is not at work today. He may/ might / could go home= He goes home, I'm not sure
Past: John was not at work yesterday. He may/ might / could have gone home = He went home, I am not sure
Can’t/ couldn’t: impossible
Present: He can’t be focused at the moment. He is so tired = It's impossible that he is focused now.
Past: He can’t have studied yesterday. He cannot answer any question.= It is impossible that he studied
yesterday
Too
too + adj (for sb/ sth) to inf = cannot
- He is too young to drive = he cannot drive = he is not allowed to drive
- The bag is too heavy (for me) to carry = I cannot carry it
Enough
(adj + enough)
enough (for sb/ sth) to + inf = sth is as much as needed
he is old enough to drive = his age is as much as needed
not enough (for sb/ sth) to + inf = sth is not as much as needed
he is not old enough to drive = his age is not as much as needed
(Enough + noun)
-I've got enough sugar to make a pancake -I've not got enough money to buy a car.