主力商品的数量和销售额,一般要占商品总量和全部销售额的()。
A.20—30%
B.40—50%
C.70—80%
D.90%左右
参考答案:C
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
简述鉴定宝石时多色性的应用。