Question

"Mary, turn off the water_________you are brushing your teeth. "  "Sorry, I'll do it at once. "
A. until          B. while          C. during

Answer 1

B

解析试题分析：句意: 玛丽，当你刷牙时，关掉水龙头。对不起，我马上做。A. until 直到……为止，B. while 与……同时， C. during 在…..期间，据句意，故选B。
考点：考查连词。