The coal miners in the coal mine for 10 hours before we came to their rescue.
| A．had trapped | B．had been trapping |
| C．had been trapped | D．would have been trapped |
A ship in harbor is safe, but that’s not ______ ships are built for.
| A．what | B．whom | C．why | D．when |
Just as I got to the school gate, I realised I ______ my bank in the cafe.
| A．have left | B．had left |
| C．would leave | D．was leaving |
scientists have learned a lot about the universe, there is much we still don't know.
| A． | Once | B． | Since | C． | Though | D． | Unless |
If you come to visit China, you willa culture of amazing depth and variety.
| A． | develop | B． | create |
| C． | substitute | D． | experience |
— Can you come to a party on Saturday, Peter?
— Oh, ______I'm already going out, I'm afraid.
| A．what a pity! | B．don't ask! |
| C．how come? | D．so what? |