Only when _______ home_____ that he had left his bag in the taxi he had taken.
| A．he returned; did he realize | B．did he return; did he realize |
| C．he returned; he realized | D．did he return; he realized |
___ is known to all, China will be an _____ and powerful country in 20 or 30 years’time.
| A．That; advancing | B．This; advanced | C．As; advanced | D．It; advancing |
I remember a ____ famous scientist said that we should believe in ourselves first of all.
| A．some | B．certain | C．sure | D．other |
I think you should complain, _____, of course, you are happy with the way things are.
| A．until | B．although | C．when | D．unless |
Rescuers had to _____ the search because of worsening weather conditions.
| A．call off | B．take off | C．come off | D．cut off |
—Are you sure Mike will help us if we are in trouble?
— _____. He is a reliable friend.
| A．It doesn’t matter | B．Don’t take it to heart |
| C．You can count on it | D．No problem |