室外热力管网设计时应掌握哪些技术资料?
参考答案:
网路的平面布置图(平面图上应标明管道所有的附件和配件),热用户热负荷的大小,热源的位置以及热媒的计算温度等。
A first-grade teacher use ten flash cards, numbered 1 through 10, to teach her students to order numbers correctly. She has students choose four flash cards randomly, then arrange the cards in ascending order. One day, she removes the cards numbered "2" and "4" from the deck of flash cards. On that day, how many different correct arrangements of four randomly selected cards are possible ?()
A.70
B.210
C.336
D.840
E.1,680
市场风险的风险事故是( )。
A.金融市场主体发生意外变动B.因内部控制缺失或疏忽C.金融市场价格发生意外变动D.因流动性短缺