离心通风机产生的表压低于(),对气体起输送作用。
A、15kPa
B、100kPa
C、300kPa
D、500kPa
参考答案:A
— I'll be away on a business trip. Would you mind looking after my pet cat?
— Not at all. ______. [ ]
A. I've no time
B. I'd rather not
C. I'd be happy to
D. I'd like it
地面上A、B两点间的水平距离为100m,工程图采用1:1000的比例尺,则图上长度为多少?