We use MUST HAVE + PAST PARTICIPLE to make logical conclusions, or deductions, about what happened in the past. Here, "must" shows that this is a very logical, or the only logical, explanation for something that happened. I feel 90-95% sure. We use COULDN'T / CAN'T HAVE + PAST PARTICIPLE to show that this explanation for something that happened in the past is NOT POSSIBLE, or absolutely impossible. It shows that I don't believe it at all.
Terms in this set (8)