常用作阴性对比剂的是() A.氨气 B.氮气 C.氧气 D.氢气 E.氯气 发布时间:2017-05-26 02:24 │ 来源:www.tikuol.com 题型:单项选择题 问题: 常用作阴性对比剂的是()A.氨气B.氮气C.氧气D.氢气E.氯气
题型:单项选择题 用所给单词补全对话。Sorry, When, speech, school, have, WhatJ: __1__ events do you have at your __2__?K: We have an English __3__ contest each year.J: __4__ is it?K: It's in May.J: Do you __5__ a pop concert?K: __6__, I don't know. 查看答案