极化曲线的（）能大致反映电极反应过程的难易程度。
A、长度
B、形状
C、方向
D、交点
参考答案：B
The film The Founding of a Republic is wonderful because about 80 stars appear in it,
some of _____ are world - famous.[ ]
A. who
B. whom
C. them
D. those
在有n个结点的二叉链表中，值为非空的链域的个数为 ______。
A．n-1
B．2n-1
C．n+1
D．2n+1
