题干

下列图象对应关系叙述正确的是(  )


A:加热高锰酸钾制氧气剩余固体质量随时间变化的关系

B:氯酸钾与二氧化锰混合加热制取氧气,生成氧气的质量随时间变化的关系

C:硫在含有氧气的密闭容器内燃烧,容器内原子个数随时间变化的关系

D:电解水生成气体质量随时间变化的关系

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答案(点此获取答案解析)

B

同类题4

阅读下列短文,从每题所给的选项中选出最佳答案。

    During my elementary (基础的) school years, I used to compare my mom with my best friend Tiffany's mom.

    Tiffany's mom always gave her lots of money to buy the most fashionable clothes and favorite food. Her mom allowed her to do anything she liked. I really admired Tiffany. My mom didn't give me much pocket money and she always told me that I should behave myself. I was angry with her.

    Whenever I didn't get what I wanted, I would complain to my mom, Tiffany's mom would give her that! I wish she were my mom. Every time, my mom would calmly say "Poor Tiffany". I couldn't understand her. "She shouldn't be feeling sorry for Tiffany!" I thought. "She should be feeling sorry for me."

    One day, I couldn't help saying to Mom, "Poor Tiffany? Lucky Tiffany! She gets everything she wants! Why do you feel sorry for her?" Iburst into tears.

    My mom sat down next to me and said softly. "Yes, I do feel sorry for her. I have been teaching you a lesson that she will never be taught."

    I looked up at her. "What are you talking about?" Mom said with care, "One day she will really want something. Maybe she'll find out that she can't have it. Her mother won't always be around to give her money, and what's more, money can't buy everything."

She continued, "I have taught you useful lessons by not giving you everything you want. You'll know how to be yourself and save money, but she won't. You'll understand that you need to work hard to get the things that you want but she won't. When Tiffany is a grown woman, she'll wake up one day and she will be wishing that she had a mom like the one you've got. Life lessons are more important than modern clothes and delicious food."

    It took some time, but I finally understood my mom's words. Now I am a happy and successful woman.