营运资本系指企业的流动资产,它包括()
A.现金
B.短期证券
C.应收帐款
D.存货
参考答案:A, B, C, D
He often come to work early and he is ____ late for work.
A.usually
B.never
C.often
D.always
通常用ELISA测定的OCV应()
A.<5%
B.<10%
C.>10%
D.<15%
E.>15%