口对口人工呼吸时，吹气的正确方法是（）。
A、病人口唇包裹吹者口唇
B、闭合鼻孔
C、吹气量至胸廓扩张时止
D、频率为8-12次/min
参考答案：B,C
It is the education ______ he received when studying abroad ______ has made him such an excellent manager.
A．that; that
B．which; which
C．that; which
D．where; that
在易飞ERP系统的主生产排程子系统中，排程来源有（）。
A.销售预测和BOM用量
B.客户订单和工单
C.采购单和客户订单
D.客户订单和销售预测
