标准试剂的称量采用分析天平灵敏度()。
A、0.1mg
B、0.01mg
C、0.001mg
参考答案:A
A random variable that has a countable number of possible values is called a:()
A. discrete random variable.
B. continuous random variable.
C. probability distribution.
外汇包括( )。
A.信用卡 B.本币C.外币 D.外币有价证券