原定位于中档产品市场的企业掌握了市场优势之后，决定向产品大类的上下两个方向延伸，这种产品组合策略叫（）。 ["向下延伸","双向延伸","向上延伸","缩减产品组合"]
新生儿窒息复苏的预防有哪些？
To determine if a C02 fire extinguisher is fully charged, you would（）. ["operate the trigger valve","weigh the extinguisher","test with a pressure gauge","read the date of last test"]
同一客户申请办理一笔存款证明能同时证明最多（）账户的存款情况。 ["A.1","B.3","C.6","D.10"]
不可分离性，即服务的（）和消费过程同时进行。 ["生产过程","消费过程","营销过程","销售过程"]
什么是子宫胎盘卒中？
