Entering the lecture hall, ____ from their clothing.

Entering the lecture hall, ____ from their clothing.
A、snow beat off
B、they beat off snow
C、snow was beaten off by them
D、they were beaten off snow
【正确答案】：B
【题目解析】：B 现在分词作时间状语， 其逻辑主语是they.再看：他们把雪从身上打掉，是一种主动语态，故为A. beat off 拍打