管段的热膨胀量应怎样计算?
参考答案:
如热力管道是在环境温度下安装的,当热力管投入运行时,管道受热而膨胀伸长,管道的热膨胀量可按下式计算:
△L=aL(t2—t1)
Every year, many competitors from famous university come to the Thames to compete each other boating.
A.for; against
B.against; with
C.with; in
D.in; with
简述孟子的经济思想的财富观。