Definition: used to express certainty that something in the past was impossible or didn't happen Level: B2
他不可能是弄坏你自行车的人——他整晚都和我在一起。
He ___couldn't ___have damaged your bike - he was with me all evening.
那本书上星期不可能在售——它今天才出版！
That book ___couldn't ___have been on sale last week - it's only come out today!
我们都确信那不可能是什么别的东西，一定是鬼魂！
We were all sure that it ___couldn't ___have been anything but a ghost!
