M: It’s like an oven here. You must be roasting. Can I open a window and get some fresh air in?
W: Actually, I’m just fine with it. But just go ahead, if you like.
Q: How does the man think of staying in the room?（）

一条输水管，长l=1000m，管径d=0．3m，设计流量Q=0．055m3／s，水的运动黏度v=1×10-6m2／s，如果要求此管段的沿程水头损失为3m，试问应选择相对粗糙度为多少的管道（）。 点击查看答案

A．Because someone may like it and then keep it.B．Because it is trivial compared to crimes and cases alike,C．Because the police are not supposed to help people do this.D．Because there are hundreds of similar guitars. 点击查看答案