国家关于发展热电联产规定,供热式汽轮发电机组的蒸汽流既发电又供热的常规热电联产总热效率年平均大于( )。
A.40%
B.45%
C.50%
D.55%
参考答案:C
患者女性,27岁。停经13周要求终止妊娠()
A.药物流产
B.负压吸引术
C.钳刮术
D.依沙吖啶(利凡诺)引产
E.水囊引产
The most variable factor in the control of broken stowage is().
A.the use of excessive amounts of dunnage
B.the use of excessive amount of filler cargo
C.the failure to stow some item in neat and uniform rows and tiers
D.the skill, industry and interest of the longshoremen