初拟正常蓄水位和其他特征水位,初拟装机容量与机组机型,是()阶段的主要内容之一。
A.项目建议书
B.预可行性研究
C.可行性研究
D.初步设计
参考答案:B
已知a与b互为相反数,c与d互为倒数,则(a+b)5+2007cd-1=______.
There _____ a pen and a ruler on the desk.[ ]
A. seems to be
B. seem to be
C. is seeming to be
D. are