ADVANCED VERB FORMS EXERCISE 3: SHOULD/COULD/MIGHT HAVE (ESL)

Grammar review Should have / could have / might have + past participle

All three look alike on the surface — modal + have + past participle — but each one makes a different claim about the past. Getting the choice wrong doesn't just sound slightly off; it changes what actually happened.

Should have + past participle: regret or criticism
Says an action didn't happen, but it was the right or expected thing to do.
“You should have called me.” (you didn't call — and you should have)
“He shouldn't have said that.” (he did say it — and he shouldn't have)

Could have + past participle: a missed possibility
Says someone had the ability or opportunity to do something, but didn't use it.
“She could have helped, but she just watched.”
Negative form is different: couldn't have means impossible, not "didn't but could have": “It couldn't have been John — he was with me all evening.”

Might have + past participle: uncertain speculation
Says something is a possible explanation, but you're not sure.
“She's not answering. She might have lost her phone.” (one guess among several — we don't know)

Quick test: Ask yourself what you're actually saying. Judging what someone ought to have done → should have. Pointing out an option that went unused → could have. Guessing at an explanation you can't confirm → might have.

This is the third and final exercise in the Advanced Verb Forms series. See also Exercise 1: Past Perfect in Reported Thought and Exercise 2: Never Would Have....