Clouds are made of small drops of water or tiny pieces of ice. The water and ice in clouds come from the Earth ’s surface,especially from lakes,rivers,and oceans. Water on the surface is heated. It changes into a gas called water vapor(水蒸气). Water vapor goes up into the air.

The higher up you go,the colder the air gets. When water vapor gets cold,it changes back into drops of water. If it gets cold enough,the water changes to ice. When the drops of water and bits of ice are so small,you see the water and ice in the sky as clouds. Scientists who study weather divide clouds into three families. Three families are called high clouds,middle clouds,and low clouds.

High clouds are made of bits of ice. High clouds can be 5 miles or more above the Earth’s surface. Rain and snow do not fall from these clouds.

Middle clouds are made of drops of water. They form about 2 to 4 miles up in the sky. You can see through them,but you can’ t see the Sun and the Moon clearly because of them.

Low clouds are made of drops of water. Most low clouds are less than a mile high. Rain or snow usually falls from these clouds.

1.Where do the water and ice in clouds come from?

The water and ice in clouds come from____________.

2.When does the water vapor change back into drops of water?

When water vapor____________,it changes back into drops of water.

3.Why can’ t you see the sun and the moon clearly?

You can’t see the sun and the moon clearly because of _____________.

4.What does “It” refer to in the first paragraph?

It refers to______________.

5.Where does the rain or snow usually fall from?

Rain or snow usually falls from________________.

Have you ever heard of “a ball of energy”? People often use it to describe very active children. But today we tell about an invention called the socket, that is a real soccer ball of energy. Julia Silverman explains that in fact the socket is a portable generator.

Julia Silverman and Jessica Matthews developed the socket as part of a group project for an engineering class at Harvard University. There are mechanisms in a socket. When you kick, hit or throw it, energy is then kept in it by these mechanisms instead of disappearing into the environment.

Then the user can put something directly into the ball, like a lamp, or a mobile phone charger so that they can get energy from it. For every fifteen minutes of the game play, the socket can provide enough electricity for an LED lamp for three hours, and the ball can store up to 24 hours’ electricity.

The International Energy Association reported last year that nearly one and a half billion people in the world had no electricity to use, and most of them live in sub-Saharan Africa and in India and other countries in Asia.

Julia Silverman and Jessica Matthews both had experiences in developing countries before they began the project. They knew that power shortages are a serious problem in really areas. There’s an energy crisis in the world. One out of every five people in the world don't have any electricity, there are a lot of health problems because what people use instead of any electricity are harmful choices like kerosene lamps, which produce a lot of smoke.

Julia Silverman says the socket ball is one small solution to a big problem. Jessica Matthews and Julia Silverman hope their socket ball will shine more light on the problem of power shortages. It offers people a chance to put their energy into the world’s most popular sport and get some energy in return.

1.From the passage, we know the socket is__________.

A.an active child B.an invention C.a lamp D.a mobile phone

2.The underlined word “crisis” in the passage means a time of__________.

A.difficulty B.safety C.success D.sadness

3.We can infer from the passage that__________.

A.active children care more about playing socket

B.people are expected to get some energy by playing socket

C.Julia Silverman has never been to developing countries before

D.kicking a socket can let the energy disappear into the environment

4.The best title for the passage should be__________.

A.A soccer ball that gives energy B.The way to help save electricity

C.The best way to solve energy problems D.An invention changing the world

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