由权值为1,2,3,4,5,6的六个叶子结点构成一棵哈夫曼树，则带权的路径的长度为______。
参考答案：55
Can you see _____________?
A．what he’s reading
B．what is he reading
C．what does he read
D．he reads what
±800kV直流线路的电阻损耗是±500kV直流线路的（）%。
A.39
B.49
C.59
D.69
