每()检查1次水过滤器,必要时清洗并清除堵塞物。
A、班
B、日
C、周
D、月
参考答案:C
—When did it begin to snow?
—It started ______ the night. [ ]
A. during
B. by
C. from
D. at
群众性精神文明创建活动,以()为主体。
A.讲文明、树新风
B.创建文明城市
C.创建文明村镇
D.创建文明行业