The chemistry teacher required the students___more attention___the lab clean
| A．to pay;to keep |
| B．to paying;to keeping |
| C．to pay;to keeping |
| D．paying;keeping |
Don't you know _____, my dear friend, it is you that she loves?
| A．who | B．which | C．that | D．what |
Most air pollution is caused by the burning of _________ like coal, gas and oil.
| A．fuels | B．articles |
| C．goods | D．products |
I bought a dress for only 10 dollars in a sale; it was a real _________.
| A．exchange | B．bargain |
| C．trade | D．business |
—Shall we go out for a walk?
—Sorry. This is not the right _________ to invite me. I am too tired to walk.
| A．moment | B．situation |
| C．place | D．chance |
The top leaders of the two countries are holding talks in a friendly _________.
| A．atmosphere | B．state |
| C．situation | D．phenomenon |