在半导体存储器中，动态RAM的特点是（）。
A、信息在存储介质中移动
B、每隔一定时间进行一次刷新
C、按字结构方式存储
D、按位结构方式存储
参考答案：B
We must do it well, ________ there are a lot of difficulties. [ ]
A. as if
B. as though
C. even though
D. even as
对策的三要素有哪些？
