Verbs do much more than express an action, such as 'running'. There are also helping verbs, like 'be' that 'help' express the tenses of other verbs, as in 'I am running (now)', 'I was running (before)', etc.
A specific set of helping verbs are 'modal verbs', which tell us the 'mood' of the sentence:
- Is the speaker certain of what they say (or is it just a possibility/prediction/expectation)?
- Is the speaker asking/demanding someone to do something?
- Is the speaker asking for or giving permission to do something?
The following are some of the most frequently used modal verbs in the English language:
Ability:
- I can help you.
- She can’t understand you.
- When I was a child, I could see ghosts.
Possibility:
- The story can be true.
- He could be telling the truth.
Ask/Give Permission:
Request:
- Can you help me?
- Could you help me?
Obligation:
- You must come back before 10!
- Must I arrive there early?
Prediction:
- He must be smart if he studies so hard.
Ask/Give Permission:
- You may stay here.
- May I ask your name?
Prediction:
- He may come to the party.
- He might come to the party.
Personal opinion/ advice/ recommendation:
- You should believe in yourself.
- He shouldn’t be late for school.
Expectation:
- You should (be able to) succeed.
- Our team should (be able to) win this match.
When expressing an expectation, we often use 'should' with 'be able to'. We could omit 'be able to' in the sentences above: "You should succeed" and "Our team should win". However, without 'be able to', it is less clear if the sentences are recommendations or expectations.
Willingness:
- I will come visit you tomorrow.
- I will not (won’t) come back.
- He said he would do it again.
Prediction:
- I think it will snow tomorrow.
- I thought that it would snow yesterday.
Polite Request:
- Will you open the door for me, please?
- Would you help me carry this, please?
