下面属于电子商务信息发布和传输层是()
A.CA认证
B.HTTP
C.EDI
D.E-mail
参考答案:B, C, D
—This new model bike _____ Uncle Wang last week.
—How beautiful! By the way, what’s it _____?[ ]
A. was made by; made of
B. was made; made from
C. was made to; make up
D. made by; made of
检验假设的方法有两种:______和______。