下列食物中,铁的良好来源是
A.动物肝脏
B.鱼
C.蛋黄
D.大豆
E.小麦
参考答案:A
Anyone breaking the rules will be asked to leave .
A.at the spot
B.on the spot
C.for the spot
D.in the spot
热阻R与传热总系数K之间的关系是()。
A.1/R
B.10R
C.100R
D.R