–Did you find your new dictionary?
---Yes. I found it ____I had left it.
| A．in where | B．in the place which |
| C．where | D．which |
Some English scientists are identifying problems ____ technology in the 21st century. If solved, the solutions could change the world.
| A．facing | B．faced | C．being faced | D．having faced |
Exactly ____they did when at last they reached the sea remains a complete mystery.
| A．that | B．how | C．which | D．what |
One thing’s for sure, the fire _____by some cigarette butts.
| A．might cause | B．could have caused |
| C．must have been caused | D．should be caused |
You could ________ this a really nice room if you bought a new carpet.
| A．make | B．turn | C．grow | D．get |
--- You’ve sold your car! You don’t need one?
--- _____. The traffic is too heavy nowadays.
| A．No problem. | B．Never mind. | C．Don’t mention it. | D．Not really |