问题 单项选择题

用TLC检测化合物的纯度时,多采用()

A.一种展开系统

B.二种展开系统

C.三种展开系统

D.四种展开系统

E.一种展开系统并更换多种显色方式

答案

参考答案:C

单项选择题
写作题

2010年广州亚运会即将来临。为了迎接亚运,你们班级将举行一次“我与2012广州亚运”的主题班会。假如你是班长,请你就以下内容拟一个发言稿。
[写作内容]
2010年广州亚运会
1. 是21世纪初重大体育赛事之一;
2. 包括中国在内的亚洲各国都在为此做准备;
3. 亚运会的作用;
省、市政府
1. 修建体育场馆、亚运村等;
2. 美化城市;
我们中学生
1. 学好英语,争做自愿者;
2. ……
[写作要求]
1.只能使用5个句子表达全部内容;
2.文中不能出现真实姓名和学校名称;
3. 注意:发言稿的开头和结尾已给出(不计入5个句子中)。
Hello, my dear fellow classmates. Today we’re having a class meeting here whose topic is “2012 Guangzhou Asian Games & Me”.                                                                             
                                                                                
                                                                                
                                                                                                                                                                   
                                                                                                                                                                                                                                                   
                                                                                
                                                                                
Thank you for your attention and next, I hope all of you will share your idea with one another about the coming great Games.