问题 单项选择题

测定水样BOD5,如水样中无微生物,则应于稀释水中接种微生物,可采用( )。

A.(A) 每升稀释水中加入生活污水上层清液1~10mL

B.(B) 每升稀释水中加入表层土壤浸出液50~100mL

C.(C) 每升稀释水中加入河水、湖水50~100mL

D.(D) 每升稀释水中加入湖水1~10mL

答案

参考答案:A

解析:
测定水样BOD5,如水样中无微生物,则应于稀释水中接种微生物,可采用每升稀释水中加入生活污水上层清液1~10mL,或每升稀释水中加入表层土壤浸出液20~30mL,或每升稀释水中加入河水、湖水10~100mL

阅读理解

阅读理解。

      A lot of boys and girls in western countries are wearing the same clothes, and many boys have long

hair, so it is difficult to tell whether they are boys or not.

      One day an old man went for a walk in a park in Washington and when he was tired, he sat down

on a chair by a swimming pool. A young person was standing on the other side of the pool.

     "Oh!" the old man said to the person sitting next to him, "Do you see the person with the loose

clothes and long hair? Is it a boy or a girl?"

      "A girl," said the person, "She is my daughter. "

      "Oh!" the old man said quickly, "Please forgive me. I don't know that you are her mother. "

      "I'm not," said the person, "I'm her father. "

1. What did the old man see on the other side of the pool?

A. A girl. 

B. A boy. 

C. An old woman. 

D. A man. 

2. The old man thought the person sitting next to him was ____. 

A. a woman

B. a man

C. a girl

D. a boy

3. "Please forgive me." in the passage means "____" .

A. I'm not sure. 

B. I'm surprised.  

C. I'm sorry. 

D. I'm not living here. 

4. Which is right according to the passage?

A. Most people in western countries wear the same clothes. 

B. The old man thought the person next to him was a man. 

C. It's difficult to tell boys from girls because they wear the same clothes. 

D. Sometimes men also have long hairs as women in western countries. 

5. Which can be the best title for the passage?

A. Are they wearing the same clothes?

B. Can you tell boys from girls?

C. Are they boys or girls?

D. What's wrong with the boys?

单项选择题