单选：在决定样本规模所需考虑的各个因素中，()不是必须的，即它需要根据抽样对象的具体情况决定是否进行。A．确定可信赖程度B．确定可接受的抽样风险C

Life gets noisier every day and very few people can free from noise of some s...

When did you last see a polar bear? On a trip to a zoo,perhaps? If you had at...

家中预防煤气中毒的措施有哪些？（）A．临睡前，一定要关闭煤气阀门B．平时严格检查煤气管道、阀门是否漏气，应及时检修，严格遵守使用规则C．烧煤厨房应有风斗，充分通风换气D．安装CO报警器后就不用担心会发生煤气中毒

" ... She was married to an officer in India , long ago India； and she had a...A

[ 英译汉 ]This box can hold more books than that one.