Question

【题目】根据材料内容，选择正确答案。
D
Look up in the sky. Do you see any clouds? What do they look like? Some clouds are fluffy(绒毛状的) and white, like cotton balls. Others are dark almost black, and make you hold an umbrella. At sunrise and sunset, clouds can look red, purple, or yellow---as if they were colored with crayons. But what are clouds anyway?
You can't reach out and touch the clouds, but you can make your own in a bottle.
You need
* an adult helper
* a huge, empty glass jar
* a metal strainer(过滤器)
* hot water
* ice
Do these
Step1. Have your helper fill the jar with hot water, leave it there for two minutes, then pour out most of the water. Leaving just an inch or two at the bottom of the jar.
Step2. It's your turn, put the strainer over the mouth of the jar, fill the strainer with ice. Watch the jar.
What happened?
A cloud formed in the jar! Some of the hot water at the bottom of the jar turned into hot water vapor(蒸汽). The water vapor rose and met with the cold air coming off the ice. When the water vapor condensed, it formed a cloud. Hot air rises and carries with it lots of water vapor, the higher the air rises, the more it cools down. Soon the cold air can't hold all the water vapor so it starts turning into tiny water drops, and becomes a cloud.
（1）This text mostly about .
A.the weight of a cloud
B.what makes a cloud
C.the colour of clouds
D.why clouds are fluffy
（2）What do you need for Step 1?
A.A jar.
B.A strainer.
C.Ice.
D.Crayons.
（3）The main purpose of the last paragraph is to show .
A.the importance of the experiment
B.the reason of the experiment
C.the result of the experiment
D.the steps of the experiment

Answer 1

【答案】
（1）B
（2）A
（3）B
【解析】1. 文章第四行You can't reach out and touch the clouds, but you can make your own in a bottle.你不能伸手去摸云,但是你可以用瓶子自己做。文章还提到了，需要的东西，以及步骤做法，最后还提到了 and becomes a cloud.成为云。故选B。2.文章吧倒数第七行Step1. Have your helper fill the jar with hot water, leave it there for two minutes, then pour out most of the water. Leaving just an inch or two at the bottom of the jar.step1 .有你的帮手用热水把罐子装满,把它放在那里两分钟,然后倒出大部分水。在罐子底部只留下一两英寸。A jar.一个罐子。A strainer.一个过滤器。Ice.冰。Crayons.蜡笔。故选A。3.the importance of the experiment实验的重要性。the reason of the experiment实验的原因。the result of the experiment实验的结果。the steps of the experiment实验的步骤。文章最后一段的大意：在罐子里形成的云!罐子底部的一些热水变成了热水蒸汽(蒸汽)。水蒸气升上了冰,冷空气从冰上掉下来。水汽凝结后形成云。热空气上升并携带大量水蒸气,空气越高,冷却越多。不久,寒冷的空气不能容纳所有水蒸气,所以它开始变成小水滴,变成云。故选B。