The surprising experiment I am about to describe proves that air is all aroud you and that it proves down upon you．Air pressure is a wonderful force．When you swim underwater, you can feel water push down your body．The air all around you does the same．However, your body is so used to it that you do not notice this ．The pressure is caused by a layer of air called the atmosphere．This layer surrounds the Earth , extending to about five kilometers above the Earth’s surface．
The following experiment is an easy one that you can do at home．But make sure that you are supervised , because you will need to use matches．Now for the experiment！
What you need
·A hard-boiled egg without the shell
·A bottle with a neck slightly smaller than the egg
·A piece of paper
·A match
Metheod
1) Check that the egg will sit firmly on the neck of the bottle．
2) Tear the paper into strips and put the strips into the bottle．
3) Light the paper by dropping a burning match into the bottle．
4) Quickly sit the egg on the neck of the bottle．
Result
Astonishingly,the egg will be sucked into the bottle．Your friends will be amazed when you show them the experiment．But be careful when you handle matches．
Why it happened
As the paper burns,it needs oxyen and uses up the oxygen(air) in the bottle．The egg acts as a seal in the neck of the bottle,so no more air can get inside ．This reduces the air pressure inside the bottle．The air pressure must equalize,so more air from outside must enter the bottle．The outside air pressure against the egg and then the egg is pushed into the bottle!The proves that air is all around and that it is pressing down on it．
53．When you do the experiment, why need you a person beside you?
A．You couldn’t place the egg on the bottle by yourself．
B．The egg needs to be shelled．
C．You need to use matches．
D．The bottle can’t sit firmly on the desk．
54．The purpose of doing this experiment is to prove ______．
A．air pressure is a wonderful force
B．water can push down your body when you swim underwater
C．the air pressure is not equalized around us
D．the earth is surrounded by a layer of air called the atmosphere
55．How did the egg put into the bottle？
A．The oxygen inside the bottle suckde the egg in．
B．It became solt without the shell．
C．The neck of the bottle was wide enough．
D．The outside air pressure forced it into the bottle．
56．The passage is ______．
A．an experiment report            B．a scientific story
C．a research report                 D．an interesting novel

Without plant, people could not live. We eat plants. We breathe the oxygen（氧气）that plants produce. And we need plants for another reason: we need them for their beauty.

Imagine a world with no plants. Imagine no flowers with their sweet smells, their beautiful colors and their lovely shapes. Imagine when the wind blows, not being able to hear the leaves in the trees or watch the branches sway（摇摆）from side to side.

Everywhere people need the beauty of plants. That is why we have parks full of trees and flowers. That is why people always try to design houses with room for some grass and a garden.

Do you talk to your plants? Do you give them love and attention?

Peter Tompkins and Christopher Bird, writers of a book called THE SECRET LIFE OF PLANTS, tell of an experiment in which two seeds were planted in different places. While the plants were growing, one plant was given love and hopeful ideas. The other plant was given only hopeless ideas. After six months, the loved plant was bigger. Under the earth it had more and longer roots; above the earth, it had a thicker stem (茎) and more leaves.

1.According to the passage, which of the following is right?

A．If there are no flowers, there will be no sweet smells.

B．Without plants, we can’t hear the wind.

C．We plant trees to watch the branches sway from side to side.

D．We need plants not only for food and oxygen but also for their beauty.

2.In the experiment, the plants were________.

A．of different kinds                       B．talked to in two different ways

C．both given love and attention              D．grown in the same place

3.At the end of six months,________.

A．one plant had longer roots than the other and had a thicker stem

B．one plant had longer roots while the other had a thicker stem

C．the plants were of the same size

D．one plant had a thicker stem while the other plant had more leaves

4.The experiment has proved（证明） that________-.

A．we should talk to plants and give them love

B．without plants people could not live

C．we should grow as many plants as possible

D．plants need plenty of water, sunshine and attention

Scientists in Israel have discovered a new way to test for water pollution by “listening” to what the plants growing in water have to say.

By shining a laser beam (激光束) on the tiny pieces of algae floating in the water，the researchers said they hear sound waves that tell them the type and amount of contamination (致污物) in the water.

“It is a red light，telling us that something is beginning to go wrong with the quality of water，” said Zvy Dubinsky，an aquatic biologist at Israel’s Bar Ilan University.“Algae is the first thing to be affected by a change in water quality.”“The secret，” he said，“is to measure the rate of photosynthesis (光合作用) in the algae，meaning the plant’s ability to transform light into energy.” During photosynthesis，plants also release oxygen into the air.

Dubinsky’s technique is easy to perform because of the over?abundance of algae in the planet’s water.Most of the oxygen in the atmosphere comes from algae.A prototype tester that occupies about one square meter of a laboratory desktop，shoots a laser beam at water samples to stimulate photosynthesis in the algae.But not all of the laser’s heat is used.Depending on the condition of the algae and the rate of photosynthesis，some of the heat is shot back into the water，creating sound waves，Dubinsky said.With a special underwater microphone，researchers are able to analyze the strength of the sound waves and determine the health of the algae and the condition of the surrounding water.

“Algae suffering from lead poisoning，like waste discharged from battery and paint manufacturing plants，will produce a different sound than those suffering from lack of iron or exposure to other toxins，” said researcher Yulia Pinchasov.She said that testing algae photosynthesis can determine water quality more accurately and easily than labor?intensive methods now used like chemical and radioactive carbon testing.

1.The underlined word “algae” in Paragraph 2 probably refers to a kind of________.

A．instrument? B．plant

C．wood? D．pollutant

2.Why is the algae tested?

A．Because it floats on the water.

B．Because it can have photosynthesis.

C．Because it is the first to be polluted.

D．Because it can produce different sounds.

3.We can infer from the passage that________.

A．algae can produce a loud sound when polluted

B．algae can die easily from pollution

C．photosynthesis of the algae can only be caused by sunlight

D．photosynthesis of the algae is related to water quality

4.What would be the best title for the passage?

A．Scientists Listen to Plants to Find Water Pollution

B．A Prototype Tester Is Used to Determine Water Pollution

C．The Importance of Photosynthesis of the Algae

D．The Problem of Chemical and Radioactive Carbon Testing

A breathtaking trick potentially left over from our ancestors might be found in us — the ability to sense oxygen through our skin.
Amphibians, animals such as frogs that can live both on land and in water, have long been known to be capable of breathing through their skin. In fact, the first known lungless frog that breathes only through its skin was discovered recently in the rivers of Borneo.
Now the same oxygen sensors found in frog skins and in the lungs of mammals (哺乳动物) have unexpectedly been discovered in the skin of mice.
“No one had ever looked,” explained Randall Johnson, a biologist researcher.
Mice and frogs are quite distant relatives, so the fact they have these molecules (分子) in common in their skin suggests they might well be found in the skin of other mammals, such as humans.
“We have no reason to think that they are not in the skin of people too,” Johnson said.
These molecules not only detect oxygen, but help increase levels of vital red blood cells, which carry oxygen around the body. Normal mice breathing in air that is 10 percent oxygen—a dangerously low level similar to conditions at the top of Mount Everest, and about half that of air at sea level. However, mice that had the oxygen sensor HIF-1a genetically removed from their skin failed to produce this hormone (荷尔蒙) even after hours of such low oxygen.
These findings, if they hold true in humans, suggest one could raise the level of oxygen circulating inside the body. This could help treat lung diseases and disorders such as anemia (贫血症) without injecting drugs, which make up a multibillion-dollar market, Johnson said.
Athletes also often try to get more oxygen delivered to their muscles in order to improve their performance. They often do this by training at high altitudes or in low-oxygen tents. The new study suggests they might want to expose their skin as well as breathing in low-oxygen air to improve their performance. “It’s hard to say what exactly might be done, however—there’s a lot we don’t know yet,” Johnson explained.
The scientists detailed their findings in the April 18 issue of the journal Cell.
【小题1】Which of the following statements is TRUE according to the passage?

The surprising experiment I am about to describe proves that air is all around you and that it proves down upon you．Air pressure is a wonderful force．When you swim underwater, you can feel water push down your body．The air all around you does the same．However, your body is so used to it that you do not notice this．The pressure is caused by a layer of air called the atmosphere．This layer surrounds the Earth, extending to about five kilometers above the Earth's surface．

The following experiment is an easy one that you can do at home．But make sure that you are supervised, because you will need to use matches．

What you need

·A hard-boiled egg without the shell

·A bottle with a neck slightly smaller than the egg

·A piece of paper

·A match

Method

1）Check that the paper will sit firmly on the neck of the bottle．

2）Tear the paper into strips and put the strips into the bottle．

3）Light the paper by dropping a burning match into the bottle．

4）Quickly sit the egg on the neck of the bottle．

Result

Astonishingly, the egg will be sucked into the bottle．Your friends will be amazed when you show them the experiment．But be careful when you handle matches．

Why it happened

As the paper burns, it needs oxygen and uses up the oxygen （air）in the bottle．The egg acts as a seal in the neck of the bottle, so no more air can get inside．This reduces the air pressure inside the bottle．The air pressure must equalize, so more air from outside must enter the bottle．The outside air presses against the egg and then the egg is pushed into the bottle! That proves that air is all around and that it is pressing down on it．

Why is there the need to take care when you are doing the experiment?

A．The bottle could break．

B．You need to light the paper with a match．

C．The egg needs to be shelled．

D．The egg has to be perfectly placed on the neck of the bottle．

In the experiment, the burning inside the bottle can__．

A．equalize the air pressure inside and outside

B．make a seal in the neck of the bottle

C．finish up the oxygen inside the bottle

D．produce more oxygen inside the bottle

How did the egg put into the bottle?

A．The oxygen inside the bottle sucked the egg in．

B．It became salt without the shell．

C．The neck of the bottle was wide enough．

D．The outside air pressure forced it into the bottle．

The experiment is carried out to prove ____．

A．water pushes on your body when you swim underwater

B．the earth is surrounded by a layer of air called the atmosphere

C．the pressure of air around us has a powerful force

D．the air pressure is not equalized around us