The young couple, who returned my lost wallet, left _______ I could ask for their names.
| A．while | B．before | C．after | D．since |
It is so cold that you can't go outsidefully covered in thick clothes.
| A． | if | B． | unless | C． | once | D． | when |
_____ Li Bai, a great Chinese poet, was born is known to the public, but some won’t accept it.
| A．That | B．Why | C．Where | D．How |
Much time _____ sitting at a desk, office workers are generally troubled by health problems.
| A．being spent | B．having spent |
| C．spent | D．spending |
-Jim, can you work this Sunday?
-? I've been working for two weeks on end.
| A． | Why me | B． | Why not |
| C． | What if | D． | So what |
Schools should be lively places where individuals are encouraged to _____ to their greatest potential.
| A．accelerate | B．improve |
| C．perform | D．develop |