题目内容
研究长期吸入氯乙烯气体对动物肝脏的危害。一组大白鼠每天放置于含有一定浓度氯乙烯气体的染毒柜中8小时，作为处理组；另一组则每天放置于含有正常空气的同样体积染毒柜中8小时。观察3个月后，将两组动物处死，观察其肝脏变化情况。这种对照组的设计属于
查看答案
搜索结果不匹配？点我反馈
更多问题
The English way of commenting on something or somebody suggests that ________.[A] the English are modest in most circumstances [C] the English tend to display less emotion than they feel[B] the English feel no less than any other nationality [D] the English don’t take a strong interest in making comment
处罚决定的执行是整个统计违法案件查处工作的最后一个环节。( )
The observations by Tsunemi Kubodera and Kyoichi Mori was reported in the journal Proceedings of Royal Society B.
基金管理费通常按照每个估值日基金净资产的一定比率(年率)逐日计提，累计至每月月底，按月支付。( )
微信支付 
支付宝支付