冰袋降温的主要原理是增加（）。
A.对流散热
B.传导散热
C.辐射散热
D.蒸发散热
E.不感蒸发
参考答案：B
I ____to go for a walk, but someone called and I couldn't get away.[ ]
A. was planning
B. has planned
C. had planned
D. would plan
建设现代农业必须从我国国情出发，促进农业现代化与（）的同步推进。
A.工业化
B.城镇化
C.非农化
D.市场化
E.电气化
