在病例对照研究中，选择偏倚主要包括
A．入院率偏倚
B．奈曼偏倚
C．检出征候偏倚
D．时间效应偏倚
E．以上均是
参考答案：E
The tour guide has made the route for the school trip. We don’t need to __ that.
A. be worried about B. be afraid of C. be sorry for
深圳证券交易所的B股投资者须开设( )。
A．美元账户
B．人民币资金账户
C．港币账户
D．居住地法定货币账户
