Scientists say it may be five or ten years___________ it is possible to test this medicine on human patients.
| A．since | B．before | C．after | D．when |
We must keep our room clean, for dirt and disease go______, you know.
| A．hand in hand | B．step by step | C．from time ti time | D．one zfter another |
To their great relief, the missing child returned home, ______, after an absence of two weeks.
| A．felt tired and sound | B．tiring and soundly |
| C．feeling tired but soundly | D．tired but sound |
Have your working conditions improved?
---No, ______than before, I’m afraid.
| A．no better | B．a little batter | C．not worse | D．no worse |
The task is too much for me, so I can’t carry on ______any longer. I must get some help.
| A．singly | B．simply | C．alone | D．lonely |
I haven’t seen______ this since I collected stamps.
| A．as old a stamp as | B．so an old stamp as |
| C．stamp as old as | D．as an old stamp a |