试述暖锋过境时的天气过程和天气现象。
参考答案：
暖锋过境时，气温上升，气压下降，天气多转为云雨天气，可能会出现连续性降水或雾。
平衡膳食应满足的基本要求有（）。
A.供给必需的能量和营养素
B.各种营养素间的比例均衡
C.合理的烹调加工
D.尽量生食以保证营养素不丢失
E.一日三餐，热能分配比例适宜
Tom was a student at this university from 1999 to 2003, ____ he studied very hard and was made
Chairman of the Students' Union. [ ]
A. for which time
B. during which time
C. during whose time
D. by that time
