旅客托运的行李在50kg以内，按行李运价计算，超过50kg时（行李中有残疾人用车时为75kg），对超过部分按四类包裹计算。（部竞赛题）
参考答案：错
I had just stepped out of the bathroom and was busy drying myself with a towel ________ I heard the
steps. [ ]
A. while
B. when
C. since
D. after
船舶机舱发生火灾时，利用水枪可能蔓延的设备、油柜、舱壁等进行冷却，以防灾情扩大.
