电子商务系统支持的在线交易的方便性和安全性也是系统健康运行的重要因素,因此电子商务系统评估还应包括()
参考答案:技术评价
I __work out the maths problem.Lily____know the answer.Let's ask her for help.[ ]
A.can't must
B.can't may
C.may not , has to
D.have to ,can
设,则f(x)=()
A.
B.
C.
D.