用0.5%氯已定酒精溶液进行手消毒时,可保持手的清洁在2小时左右,这种作用称为() 发布时间:2017-06-19 22:19 │ 来源:www.tikuol.com 题型:单项选择题 问题: 用0.5%氯已定酒精溶液进行手消毒时,可保持手的清洁在2小时左右,这种作用称为()A.拮抗作用B.后效作用C.吸附作用D.分解作用E.增强作用
题型:单项选择题 设全集U={1,2,3,4,5,6,7},A={2,4,5,7},B={3,4,5},定义A*B={x∈U|x∈A或x∈B},则A*B等于 [ ]A.{1,6}B.{4,5}C.{1,2,3,6,7}D.{2,3,4,5,7} 查看答案
题型:单项选择题 To learn English well, we should find opportunities to hear English ______ as much as we can. [ ]A. speak B. speaking C. spoken D. to speak 查看答案