按道氏理论的分类，趋势分为()等类型。
A.主要趋势
B.次要趋势
C.短暂趋势
D.无趋势
参考答案：A, B, C
普光气田控制系统各设备间的通讯是通过（）为平台建立的。
A.工业以太网
B.RSLINK
C.PCM
D.CCTV
Just last week, for example, the World Health Organization (WHO) announced the disturbing disclosure that SARS may be pretty deadlier than previously believed.
A．very
B．far
C．especially
D．none
