Unit 10
Lesson 2
SB page 73
GRAMMAR
Modal verbs of possibility in the past
● We can use modal verbs with the perfect infinitive (have + the past participle) to talk about possibility in the past.
● We use could have + the past participle or might have + the past participle for a specific possibility in the past (when we are not sure if something happened or not).
● We use must have + the past participle for a deduction about the past when we believe that something is true and quite often when we have evidence.
● We use can’t have + past participle or couldn’t have + past participle to talk about something we are certain about. We also use these to express disbelief or surprise.
● We use would have + past participle or wouldn’t have + past participle to talk about a definite outcome in the past, if the situation had been different. In this case, the if is not spoken.