问题
多项选择题
根据老年人的心理特征，老年人比较偏好（）。
A.历史悠久产品
B.健康品
C.保健用品
D.长寿用品
答案
参考答案：A, B, C, D
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根据老年人的心理特征，老年人比较偏好（）。
A.历史悠久产品
B.健康品
C.保健用品
D.长寿用品
参考答案：A, B, C, D
| 阅读理解。 | |
and Cathy Chan. They are in the same class. They are good friends. Tony is tall and fat. He is naughty (淘气的). He likes playing football and eating. Tommy is tall and thin. He is clever. He is a football fan. His favorite person is Owens. Maria is short and fat. She likes reading comics. She has a lot of comic books. Cathy is thin. She likes playing the violin. All the children like playing but they do not like doing any housework. They are very lazy. 他们是谁？在横线上写上他们的名字。  1. ________________ 2. ________________ 3. ________________ 4. ________________ 根据短文内容，回答问题。 5. How many members are there in Snoopy Club? ______________________________________________________ 6. Are Maria and Cathy sisters? ______________________________________________________ 7. Who is Tommy's favorite person? ______________________________________________________ 8. What do they like doing? ______________________________________________________ 9. Does Tony like playing football and eating? ______________________________________________________ |
某实验小组的同学对不同体积的H2和空气的混合气体点燃时的现象进行实验，结果记录如下：
| H2的体积分数/% | 90 | 80 | 70 | 60 | 50 | 40 | 30 | 20 | 10 | 4 |
| 空气的体积分数/% | 10 | 20 | 30 | 40 | 50 | 60 | 70 | 80 | 90 | 96 |
点燃现象 | 安静燃烧 | 安静燃烧 | 弱爆炸 | 强爆炸 | 强 爆 炸 | 强 爆炸 | 强爆炸 | 强爆炸 | 强爆炸 | 不 不 爆 燃 炸 烧 |
（2）该实验小组的同学用______排空气法收集H2，保持试管倒置移近火焰，结果没有听到任何声音，他认为这表示收集的H2已经纯净．你认为他的判断对吗？
该同学的判断是______，你的理由是______．