二、单项填空（共20小题；每小题0.5分，满分10分）
21. The operation was_______success and the patient is now out of _______danger.
A. a, the B. a, 不填 C. 不填, the D. 不填, 不填
22. At last, we reached a lonely village, ________lay a beautiful river.
A. in front of it B. in front of which
C. in front of that D. in front of where
23. Scientists say it may be five or six years______it is possible to test this medicine to human patients.
A. since B. after C. before D. when
24. Every picture on show __________him of what he had seen in China.
A. reminded B. permitted C. limited D. employed
25. If you are not ____ with western table manners, you’d better do as the host or hostess does.
A. certain B. popular C. sure D. familiar
