GB151-1999《管壳式换热器》中规定：U型管弯管段的弯曲半径R应不小于（）倍的换热管外径。
A.2
B.2.5
C.3
参考答案：A
_____ weather it is! Would you like to go out for a picnic with me?[ ]
A. How fine
B. What fine
C. What a fine
D. How a fine
互连网络的直径
