单选题
1.[2008.10]When the engine broke down，the boat‘s crew found themselves ______ of the wind.
A.at the cost
B.at the mercy
C.at the rate
D.at the moment
正确答案： B
答案解析： 本题考查的是词组的固定搭配。at the cost of：以…为代价；at the mercy of：任凭…的摆布；at the rate：以…的比率；at the moment：此刻，…的时刻。