Apart from the blood that belonged to the three people, the detectives found only_______clue.
He had hardly reached home _______ an unexpected guest came to visit him.
Had they known what was coming next, they ___________ second thoughts.
I don’t know how it ___________ that our car was bumped from behind.
—How do you like your trip to Hainan?—________,I enjoyed it very much,although the weather was hot sometimes.
-----Why didn’t you ring me up?----- Sorry, I forgot your phone number. Otherwise, I _____ long before.