题目

下列实验设计不能达到实验目的的是 选项ABCD 实 验 设 计 实验目的红磷燃烧测定空气中氧气的含量探究石蜡中含有氧元素验证氢气的密度比空气小证明石墨具有导电性 答案：B根据对话内容，从方框内选择恰当的句子将对话补充完整（选项中有两项多余的)。A. but I don't know how to get there.B. 54.5 yuan each.C. What can I do for you?D. What time is the last one?E. how often do the trains come?F. It takes 40 minutes.G.but I don’t know how to get the ticket from the machine.A: Excuse me，ma’am?B:Yes? 1.A: I want to buy a train ticket, 2. B: Well, just press here.A: How much is the ticket?B: 3.A: All right. By the way,4. B: About every five minutes.A：5. B: At 11：00 pm.A. OK. Thanks for your help.B: You’re welcome.