47. Three hundred firemen raced to the hotel after a smoke detector ______ the alarm soon after midnight.
| A．set off | B．set out | C．gave away | D．gave off |
School children must be taught how to deal with dangerous.
| A．states | B．conditions | C．situations | D．positions |
When Jane began to take swimming lessons, her main _____ was the fear of water.
| A．evidence | B．crisis | C．obstacle | D．danger |
Finding information in today’s world is easy. The ______ is how you can tell if the information you get is useful or not.
| A．ability | B．competition | C．challenge | D．knowledge |
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 |