[Grammar] Should have done

[miladb]

Thank you!

 

[Raymott]

What are the uses of the structure "should have done" except for expressing regret, for ex. " I/You should have called you/me earlier", particularly in conditional sentences?
can we say for example: "If he were a hard-working student, he should have passed the exam"? ( we know that he's not hard-working and didn't pass the exam)

Thanks for your help in advance.

Given the conditions - we know that he's not hard-working and didn't pass the exam - you'd say "If he was a hard-working student, he would have passed the exam."
In other conditions:
"Given that he was a hard-working student, he should have passed the exam" (He was, but he didn't)