若比较一组成年人和一组幼儿的身高，分析数据更分散，适用以下什么值（）。
A.极差
B.方差
C.标准差
D.离散系数
参考答案：A
根据短文内容和首字母的提示，把所缺单词填写在短文后面的横线上。
In the (1) m______ world, advertising is everywhere! Some people think that ads are great. Others
(2) h______ ads, saying that they make our cities and countryside look ugly. Many ads are (3) a______
specifically at teenagers, and some young people see more than 100 advertisements a day. It's true that
some ads can be very useful! For instance, they can help you to compare two different products so that
you can buy the (4)o______ you really need. They can also help you (5)s______ money. When prices are
listed, you can go to the store with the (6)l______ price.
某有机物的结构简式为HO－CH2-CH=CH-CH＝CH－CHO。
（1）请你写出下列官能团“”、“HO－”、“－CHO”的名称：___________、_________、
_________。
（2）验证该有机物中含有“－CHO”，常采用的试剂是___________，产生的现象为________________。
（3）该有机物的性质描述正确的有_____________
A、与金属Na反应放出O2
B、能与新制Cu(OH)2反应，产生红色沉淀
C、不能发生银镜反应
D、一定条件下能与H2发生加成反应
（4）1mol该有机物完全与溴水发生加成反应时，需要Br2____________mol
”、“HO－”、“－CHO”的名称：___________、_________、