Only when ___ possible to settle the problem.
The audience __________ before TV sets are listening to Yi Zhongtian's stories with their eyes __________ upon him.
The boy insisted that he __________ the glass. He said that he was not there then.
—Sorry, sir. I'm late again.—What excuse will you __________ for yourself this time?
This box __________ all the books you need, __________ an English-Chinese dictionary.
We'd better set off or it will be dark __________ we know it.