题目

School in the cities are well equipped, ________ those in the countryside are poor. A . if B . while C . so D . as 答案：B诗人杜甫在《对雪》一诗中曾写道“北雪犯长沙，胡云冻万家”，与诗中描述有关的天气系统是A.反气旋、准静止锋B.反气旋、冷锋C.气旋、冷锋D.气旋、准静止锋