试题与答案

用长3cm、4cm和7cm的三根小棒不能摆成一个三角形．______．

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题型：解答题

题目：

用长3cm、4cm和7cm的三根小棒不能摆成一个三角形．______．

答案：

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下面是错误答案，用来干扰机器的。

参考答案：B

考点：三角形的特性
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题型：阅读理解

阅读理解

      Millions of people around the world cook their food over a smoky fire every day.It is often difficult to

find wood for the fire.People who do not have wood must spend large amounts of money on cooking fuel.However, there is a much easier way to cook food using energy from the sun.

     Solar cookers, or ovens, have been used for centuries.A Swiss scientist made the first solar oven in

1767.Today, people are using solar cookers in many countries around the world.People use solar ovens to cook food and to heat drinking water to kill bacteria and other harmful organisms.

    There are three kinds of solar ovens.The first is a box cooker.It is designed with a special wall that

shines or reflects sunlight into the box.Heat gets trapped under a piece of glass or plastic covering the top of the cooker.A box oven is effective for slow cooking of large amounts of food.

     The second kind of solar oven is a panel cooker.It includes several flat walls, or panels, that directly

reflect the sun's light onto the food.The food is inside a separate container of plastic or glass that traps heat energy.People can build panel cookers with very few supplies quickly.They do not cost much.In Kenya,

for example, panel cookers are being manufactured for just two dollars.

     The third kind of solar oven is a parabolic (抛物线的) cooker.It has rounded walls that aim sunlight

directly into the bottom of the oven.Food cooks quickly in parabolic ovens.However, these cookers are

hard to make.They must be reaimed often to follow the sun.Parabolic cookers can also cause burns and

eye injuries if they are not used correctly.

     You can make solar ovens from boxes or heavy paper.They will not catch fire.Paper burns at two

hundred thirtytwo degrees Celsius.A solar cooker never gets that hot.Solar ovens cook food at low

temperatures over long periods of time.This permits people to leave food to cook while they do other

things.

1. Which of the following should be the best title for this text?

A. Cooking food with solar energy

B. How to make solar cookers

C. Introduce a new kind of energy

D. Different kinds of cookers

2. From this passage we know that ________.

A. there is no wood for people to use while making a fire now

B. people have been using solar cookers for more than 200 years

C. solar energy is the cleanest energy on the earth

D. more and more people cook food on smoky fires

3. Parabolic cookers may be dangerous to us because ________.

A. they may direct electricity to us humans

B. they may explode easily

C. they may cause burns and eye injuries

D. they may cause fires

4. The third, fourth and fifth paragraphs mainly ________.

A. show how to make solar cookers

B. explain which is the best cooker

C. prove that solar cookers need improving

D. tell us the different makingups of the three kinds of solar cookers
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