The group is made up____five students. And they are studying hard to make up____ the lost time.
| A．of,of | B．for,for | C．of,for | D．for,of |
—Under no circumstances ________ the door to the Data Centre unlocked.
—I promise I'll be more careful in future.
| A．you need to leave | B．should you leave |
| C．need you leave | D．you should leave |
The drug used to treat this disease causes bad side effects, some of which ________ deadly.
| A．is | B．are |
| C．was | D．were |
．No sooner ________ down on bed ________ the telephone rang.
| A．had he lain; than | B．had he lied; when |
| C．did he lie; than | D．had he laid; before |
________ about wild plants that they decided to make a trip to Madagascar for further research.
| A．So curious the couple were |
| B．So curious were the couple |
| C．How curious the couple were |
| D．The couple were such curious |
Fighting an artificial greenhouse effect seems to be the greatest of environmental challenges, ________？
| A．isn't it | B．does it |
| C．doesn't it | D．is it |