31.By the time we _____the airport, the plane_____.
| A．arrived at; had taken off | B．had got to; took off |
| C．got to; had taken away | D．arrived at ; had taken away |
Faced with the hard financial ____________, all the countries in the world should learn to cooperate to get it over.
| A．situation | B．position | C．phenomenon | D．state |
Would you take my old TV in _______ for this camera?
| A．place | B．return | C．exchange | D．business |
The research showed beyond ________ that smoking contributes to heart diseases.
| A．wonder | B．doubt | C．problem | D．use |
Giving small children some money as a gift during the Spring Festival is a common ______ in China, which may seem strange to foreigners?
| A．sense | B．practice | C．ground | D．habit |
What the expert has said and done will be _______ to the department managers.
| A．value | B．benefit | C．of valuable | D．of benefit |