问题补充:
- Whats wrong with you, Madam?
- Ive lost my valuable painting. But a week had gone by I knew it was missing.
A. while
B. since
C. until
D. before
答案:
A. while
B. since
C. until
(答案→)D. before
解析:句意:——太太,你怎么啦?——我丢了我的贵重的油画。但是一周过去了,我才知道它丢了。A. while当……时候; B. since 自从; C. until 直到; D. before在……之前;。根据knew,和had gone可知,在知道之前,那幅画已经丢了,故用连词before。故选D。