Question

Put an ice cube from your fridge into a glass of water. You have a piece of string(線) 10 centimeters long. The problem is to take out that piece of ice with the help of the string. But you must not touch the ice with your fingers.
You may ask your friends to try to do that when you are having dinner together. There is a saltcellar on the table. You must use salt when you carry out this experiment.
First you put the string across the piece of ice. Then put some salt on the ice. Salt makes ice melt(融化). The ice round the string will begin to melt. But when it melts, it will lose heat. The cold ice cube will make the salt water freeze(結(jié)冰) again.
After a minute or two you may raise the piece of string and with it you will raise your piece of ice!
This experiment can be very useful to you. If, for example, there is ice near the door of your house, you must use very much salt to melt all the ice. If you don’t put enough salt, the water will freeze again.
【小題1】We must use           when we carry out this experiment.

A．a(chǎn) fridge

B．some food

C．a(chǎn) table

D．some salt

【小題2】How long will it take to carry out this experiment?

A．More than three minutes.	B．Five minutes or two.
C．Only one minute or two.	D．About ten minutes.

【小題3】We can learn something about           from the passage.

A．physics

B．biology

C．chemistry

D．maths

Answer 1

【小題1】D
【小題2】C
【小題3】C

解析試題分析：本文介紹了一個小實驗，作者基本上是按照事情的發(fā)展順序進行介紹，閱讀中注意序數(shù)詞的使用。
【小題1】根據(jù)You must use salt when you carry out this experiment.可知選D。
【小題2】根據(jù)After a minute or two you may raise the piece of string and with it you will raise your piece of ice!描述可知選C。
【小題3】冰融化成水或者水結(jié)成冰屬于化學變化，故從本文中學到的是化學知識。選C。
考點：關(guān)于一個小實驗的說明文
點評：本文淺顯易懂，各個小題都能在文中找到適當依據(jù)。只要認真閱讀短文，注意前后聯(lián)系，就能順利完成閱讀。