苷键是 A．离子交换色谱 B．聚酰胺色谱 C．葡聚糖凝胶G D．大孔吸附树脂 E．硅 发布时间：2017-04-25 10:13 │ 来源：www.tikuol.com 题型：单项选择题 问题： 苷键是A．离子交换色谱B．聚酰胺色谱C．葡聚糖凝胶GD．大孔吸附树脂E．硅胶或氧化铝吸附色谱选择合适的色谱条件分离下列各组化合物
题型：单项选择题 补全对话。A reporter is asking a student some questions.A. Would you tell me whether you often go online?B. could you tell me if your parents let you go online?C. I will play computer games.D. When we do useless things, of course it's bad.E. could you tell me what you can think of?F. It's very exciting.G. It's difficult to say whether it's good or bad.A: Excuse me, may I ask you some questions?B: Sure.A: When you talk about the Internet, 1 B: Er, many things. For example, the music, the films, the computer games and so on.A: __2 _B: No, I don't have much time.A: Would you like to tell me what you will do if you go online?B: _3 I like playing computer games, you know.A: Do you think it is good for children to go into net bars?B: 4 _ A: Why?B: Because when we do useful things, it is good. __5 _A: Thank you for your answers.B: You are welcome. 查看答案
题型：单项选择题 关于锂的结构和性质判断错误的是 [ ]①与水反应比钠剧烈 ②原子半径小于钠 ③在空气中燃烧生成氧化锂 ④它的阳离子最外层电子数与钠的阳离子相同 ⑤它是还原剂 A、①④ B、②③ C、③⑤ D、只有① 查看答案