Airpollutionisgettingmoreandmoreserious,sowemusttakeac...

來源：國語幫 2.94W

Air pollution is getting more and more serious, so we must take action　　　　it is too late.

A. before B. after C. until D. when

A。考查時間狀語從句。句意: 空氣汙染越來越嚴重, 所以我們必須在太晚之前採取措施。before在……之前; after在……之後; until直到……為止; when在……時候。根據句意故選A。