John was not here yesterday. Maybe he was ill

Knowledge: Modal verbs

Explain:

Perhaps = possibly = might: possibly, not sure

Should have Ved/V3: should have been

Might have Ved/V3: probably did (unlikely)

Must have Ved/V3: definitely (definitely high)

Couldn’t have Ved/V3: was unable to do anything (despite wanting to)

=> John was not here yesterday. Maybe he was sick.

= A. John was probably sick, so he wasn’t here yesterday.

B. John must have been sick yesterday, so he’s not here. => wrong in meaning

C. John couldn’t be here yesterday because he was sick. => wrong in meaning

D. Because of illness, John should not have been here yesterday. => wrong in meaning

Choose A