问题补充：
In the north of China, it has been snowing for weeks onend, which causes severe damage to crops; it is estimated that the heavy snowfall will come to end next week.
A. /; an
B. the; a
C. a; an
D. an; /
答案：
(答案→)A. /; an
B. the; a
C. a; an
D. an; /
解析：
试题分析:考查冠词用法。固定短语on end “持续；直立的”；come to an end “结束”，根据语境判断A选项正确。句意：在中国北部大雪持续了数周，这造对庄稼造成了严重的损害；据估计这次的降雪将于下周结束。
