---Who ______ it be that hasn’t handed it in yesterday. ---It _______ be Bob. He handed it in yesterday.
It’s said that this kind of plant only gives off this strange perfume on ________ conditions which the scientists are trying to figure out now.
As we know, success often comes after ______ failure; so don’t be so upset about _______ failure of this matter.
不填; the
It’s crazy of you to spend more time playing computer games than you _______ studying.
--Do you think you can finish the project by five o’clock this afternoon? ---_______. I’ll be busy with my term paper all day.
This hotel is the highest building in the city, from _______ top you can enjoy a good view of our city.