第4题:[单选题]In the process of separation, ___ A.water content should be removed first. B.solid impurities should be removed first. C.both water and solid impurities should be removed together. D.either of them can be removed first. 参考答案:A
第5题: [单项选择]旅游产品的核心和主体是()。 A. 旅游吸引物 B. 旅游设施 C. 可进入性 D. 旅游服务 参考答案:D