Question

- What's wrong with you, Madam?
- I've lost my valuable painting. But a week had gone by _______ I knew it was missing.

A．while

B．since

C．until

D．before

Answer 1

D

解析试题分析：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。
考点：考查连词的用法。