语法与词汇 She did her best to stay awake, but the performance was so boring that she just _____ to sleep.无
【正确答案】 C
【答案解析】句意: 她尽全力让自己清醒, 但表演实在太沉闷了, 她终究睡着了。 drop off睡着。 drop in顺便拜访。 drop out辍学。 drop down落下。 因此选C。