为避免医生以及病人对实验效应观察的主观偏性,可采用的方法是()
A.随机化
B.单盲
C.双盲
D.对照
E.多中心研究
参考答案:C
--- you disturb her with these annoying questions just when she was busy cooking dinner?
---Sorry, I that at that time.
A.Should, should have done
B.Shall; may have done
C.Must, should do
D.Must, should not have done
涉及旅游交通的法律法规有()。
A.《中华人民共和国合同法》
B.《中国民用航空旅客、行李国内运输规则》
C.《中华人民共和国公路法》
D.《中华人民共和国内河交通安全管理条例》