问题 问答题 简答题

什么是水的COD?测定COD有什么实际意义?

答案

参考答案:

水的COD即水的化学耗氧量。水的化学耗氧量指标主要用来表征水中有机物的含量。天然水中的有机物种类繁多,很难准确测定水中的有机物的含量,作为大致估量水中有机物含量,常利用有机物具有可氧化的共性,在一定条件下用氧化剂处理水样,测定其反应过程中所消耗的氧化剂的量换算成O2来表示,即为水的化学耗氧量。简称COD,单位为:毫克O2/升。常用的氧化剂有高锰酸钾和重铬酸钾。

阅读理解

阅读理解。

       

     When we talk about stars, especially women stars, it seems that they are always young, pretty and own

  attractive body shapes. But recently a  Britain's Got Talent (英国达人) star Susan Boyle has changed

 our views completely.

     Simon Cowell, one of the organizers of the talent show spoke of his surprise over Ms Boyle's voice.

 "This lady came up, and I'm thinking, 'This will take five seconds and I can go to have a cup of tea.' That

 changed when she began to sing I Dreamed a Dream from Les Miserables. She knew we were going to

 have that reaction (反应) and just to see that look of satisfaction on her face midway through . it was one

  of my favorite moments," Cowell said.

     The performance was posted online and before long, the 47-year-old Scottish woman has been famous

  all over the world.

     Speaking from her home in Scotland, Ms Boyle said that she hadn't thought of changing her

 appearance. She said that her friend helped her with make-up. "I mean, it's meaningless." She added.

     Ms. Boyle also spoke of the reason she first began to explore her musical talents. " I was kind of slow

 at school, so getting something like singing was a good way of hiding behind that and therefore it built my

 confidence.''

1. Susan Boyle had a look of satisfaction on her face when she was singing because _____.        

    A. she was confident of her singing

    B. she was satisfied with the organizers

    C. she was pretty and in good shape

    D. she sang the song I Dreamed a Dream from Lea Miserables

2. What does the underlined word "views" mean?

    A. 见解

    B. 预告

    C. 复习

    D. 景色

3. According to the passage, which is NOT true?

    A. It was the musical talents that built Susan's confidence.

    B. Susan Boyle was not good at her lessons when at school.

    C. Susan Boyle became famous because of her appearance.

   D. Simon Cowell didn't think Susan Boyle a good singer at the time sight.

4. What can we learn from Susan Boyle's success?

    A. It's never too old to learn.  

    B. It's easier to succeed at the age of 47.

   C. If you have a dream, keep trying to make it come true!

   D. If you are not able to study well, to be a singer instead.

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