Suggestions have been put forward ________ guns should be more strictly controlled in the USA.
A. before B. that C. when D. as
______ he referred to in his article was unknown to the general reader.
| A．That | B．What | C．Whether | D．Where |
After a knock at the door, the child heard his mother’s voice ______ him.
| A．calling | B．called | C．being called | D．to call |
Pop music is such an important part of society ______ it has even influenced our language.
| A．as | B．that | C．which | D．where |
The little boy came riding full speed down the motorway on his bicycle. ______ it was!
| A．What a dangerous scene | B．What dangerous a scene |
| C．How a dangerous scene | D．How dangerous the scene |
With the help of high technology, more and more new substances ______ in the past 10 years.
| A．discovered | B．have discovered |
| C．had been discovered | D．have been discovered |