全速率AMR参数设置中，ActiveCodeSet可以最多同时选用几种速率（）
A.3
B.4
C.5
D.8
参考答案：B
可采煤层
I, ______ , do not believe that the era of the pioneer is at an end; I only believe that the area for pioneering has changed.
A．for one’s part B．for one’s good C．for one D．for oneself
