题型:问答题 简答题 — Do you know that the meeting _____ this afternoon has been cancelled? — No. Thanks for telling me. [ ]A. to be heldB. held C. being held D. to hold 查看答案
题型:问答题 简答题 下列有关物质检验或鉴别方法正确的是( )A.向某固体中加入稀盐酸,若产生无色气体,则该固体中一定含有碳酸盐B.向某溶液中滴加紫色石蕊试液,若石蕊试液显蓝色,则该溶液一定是碱溶液C.抽丝灼烧,通过闻是否有烧焦羽毛气味来区分蚕丝制品和羊毛制品D.用水作试剂,通过观察溶液温度的变化来区分氯化钠和硝酸铵固体 查看答案