Modal Verbs in English
In English, modal verbs are used to convey various meanings to the main verb.
Could / May / Might: Used when the speaker is uncertain:
That could be the right bus. – This might be the correct bus.
The job you are applying for might be difficult. – The job you’re applying for could be challenging.
Must: Expresses certainty:
I am sure he must be 50. – I’m certain he’s 50 years old.
This bus must be a good model. – This bus is definitely a good model.
Couldn’t / Could: Used for making guesses and expressing certainty:
Couldn’t it be your mistake? – Could it be your error? (Guessing)
They couldn’t be here on time. – They definitely can’t be here on time. (Certainty)
Can’t: Expresses certainty:
He can’t be serious. – He can’t be serious.
This car can’t belong to her. – This car definitely can’t belong to her.
Could Have, May Have, Might Have: Used in the past when there is uncertainty:
I may have seen you before. – I might have seen you previously.
It could have been Jessica on the coach. – It might have been Jessica on the coach (uncertain).