问题 选择题

滴管正确使用方法叙述错误的是(  )

A.滴瓶上的滴管专用,取用试剂后不要洗涤立即放回原位

B.非专用滴管可连续在不同试剂瓶中吸液

C.滴管吸液后,不要平放和倒置,不得放在桌上或它处

D.用滴管向试管中滴加试剂时,滴管要悬空,不得伸入试管或与试管壁接触

答案

答案:B

题目分析:根据实验室滴管的使用方法和注意事项,(1)胶头滴管加液时,不能伸入容器,更不能接触容器.应垂直悬空于容器上方0.5 cm处.

(2)不能倒置,也不能平放于桌面上.应插入干净的瓶中或试管内.

(3)用完之后,立即用水洗净.严禁未清洗就吸取另一试剂.滴瓶上的滴管无需清洗.

(4)胶帽与玻璃滴管要结合紧密不漏气,若胶帽老化,要及时更换.

(5)胶头滴管向试管内滴加有毒或有腐蚀性的液体时,该滴管尖端允许接触试管内壁.

(6)胶头滴管常与量筒配套使用.

(7)如果滴瓶上配有滴管,则这个滴管是滴瓶专用,不能吸取其他液体;

进行解答本题.

解:

A、根据如果滴瓶上配有滴管,则这个滴管是滴瓶专用,不能吸取其他液体,用后放回原位;故A使用方法正确;

B、根据滴管用完之后,立即用水洗净.严禁未清洗就吸取另一试剂,故B使用方法错误;

C、根据滴管不能倒置,也不能平放于桌面上.应插入干净的瓶中或试管内.故C使用方法正确;

D、根据胶头滴管加液时,不能伸入容器,更不能接触容器.应垂直悬空于容器上方0.5 cm处;故D使用方法正确.

故选B.

点评:本题考查学生对实验室滴管的使用方法和注意事项的掌握及其应用.

阅读理解

阅读理解。

     One of the things to be learnt in a foreign language is guessing all the time what kind of thing to come

when listening to someone talking. People do this all the time in their own language, so it is necessary

(必要的) to do this in a foreign language, too. Here are some examples.

     1. "What's the matter?" "I went to a party last night, so I…"

     2. "I feel so tired these days."" I think you'd better…"

     3."Of course, she never stops talking. She is one of the most…"

     You can see from the above three examples that the context (上下文) helps a lot in understanding

what is being talked about. So "guessing "is very important in understanding English, especially (尤其)

spoken English.

1. This passage tells us mainly about _____.

A. the importance of "guessing " in learning a foreign language

B. how to guess what one is going to talk about

C. some examples of right guessing

D. how important it is to guess all the time

2. From the context, we can see maybe the finished answer in EXAMPLE 1 is _____.

A. "…so I didn't have a good time."        

B. "…so I went to bed very late."

C. "…so I felt unhappy."                      

D. "…

3. Maybe the finished answer in EXAMPLE 2 is _____.

A. "I think you'd better have a good rest and take good care of yourself."

B. "I think you'd better have something to drink."

C. "I think you'd better get some help from your friends."

D. "I think you'd better be more careful."

名词解释