同一类树脂其交换容量越大，则树脂的膨胀性就（）
A.越小
B.越大
C.不受影响
D.忽大忽小
参考答案：B
In the nineteenth century, poor Europeans seeking to make their fortunes turned to America as a matter of course .
A．automatically
B．obviously
C．traditionally
D．resignedly
基站巡检时接地电阻测试的执行周期为（）
A.1次/日
B.1次/月
C.1次/半年
D.1次/年
