When are windows the weak link in a building?A．In the cold winter.B．In the hot summer.C．When air conditioners are turned on.D．Both Ａ and Ｂ.

Smart Window

Windows not only let light in to cut down an electricity use for lighting, but the light coming through the window also provides heat. However, windows are not something people typically associate with being a cutting edge technology. Researchers are now working on new technologies that enable a window to quickly change from clear to dark and anywhere in between with a flip of a switch.

"It took us a long time to figure out what a window really is," says Claes Granqvist. He's a professor of solid-state physics at Uppsala University in Sweden. "It's contact with the outside world. You have to have visual contact with the surrounding world to feel well. " So, windows and natural light are important for improving the way people feel when they're stuck indoors.

Yet, windows are the weak link in a building when it comes to energy and temperature control. In the winter, cold air leaks in. When it's hot and sunny, sunlight streams in. All of this sunlight carries lots of heat and energy. And all of this extra heat forces people to turn on their air conditioners. Producing blasts of cold air, which can feel so refreshing, actually suck up enormous amounts of electricity in buildings around the world.

Windows have been a major focus of energy research for a long time. Over the years, scientists have come up with a variety of strategies for coating, glazing, and layering windows to make them more energy efficient. Smart windows go a step further. They use chromogenic technologies which involve changes of color.

Electrochromic windows use electricity to change color. For example, a sheet of glass coated with thin layers of chemical compound such as tungsten oxide works a bit like a battery. Tungsten oxide is clear when an electric charge is applied and dark when the charge is removed, that is, when the amount of voltage is decreased, the window darkens until it's completely dark after all electricity is taken away. So applying a voltage determines whether the window looks clear or dark.

One important feature that makes a smart window so smart is that it has a sort of "memory. " All it takes is a small jolt of voltage to turn the window from one state to the other. Then, it stays that way. Transitions take anywhere from 10 seconds to a few minutes, depending on the size of the window. The development of smart windows could mean that massive air conditioning systems may no longer need. "In the future," Granqvist says, "our buildings may look different. "

Which of the following statements does not indicate the importance of windows as described in the first two paragraphs?

A．Windows can change from clear to dark to save energy.

B．Windows help to save energy by letting light in.

C．Windows help to save energy by providing heat.

D．Windows enable people to have contact with the outside world.

Forces other than damaging winds are also at work inside tornadoes (龙卷风) . Sometimes,as the wind passes a house, the walls and ceiling burst apart as if a bomb had gone off inside. This explosion is caused by the low air pressure at the center of a tornado.

The pressure at the center of a tornado is usually 13 pounds per square inch. However,inside the house the air pressure is normal, about 15 pounds per square inch.The difference of 2 pounds per square inch between the inside and outside pressure may not seem like much. But suppose a tornado passes over a small building that measures 20 by 10 by feet. On each square inch of the building, there is 2 pounds of pressure from the inside

that is not balanced by air pressure outside the building. On the ceiling, that adds up to an unbalanced pressure of 57600 pounds. The pressure of the four walls adds up to 172800 pounds.

If windows are open in the building, some of the inside air will rush out through them.This will balance the pressure inside and outside the building.But if the windows are shut tightly, the huge inside pressure may cause the building to burst.

Unfortunately, heavy rain often occurs in the storms that later produce tornadoes,so people often shut their windows. This may cause far worse damage later.

21、 What did the paragraph before this passage most probably discuss?

A、 Measuring rainfall from a storm

B、 The kinds of damage caused by explosions

C、 The powerful winds of tornadoes

22、 Which of the following is the main topic of the passage?

A、 How tornadoes can be prevented

B、 When tornadoes usually occur

C、 Why tornadoes cause so much damage

23、 Tornadoes can destroy buildings because the()

A、 force of a tornado increases the air pressure in a building

B、 air pressure inside a tornado is less than the air pressure inside a building

C、 air pressure at the center of a tornado is over 172000 pounds

24、 What is the difference per square inch between the air pressure inside a building and the air pressure inside a tornado?

A、 2 pounds

B、 13 pounds

C、 15 pounds

25、 What would happen if the windows are shut tightly in the stormy weather?

A、 Tornadoes may be formed

B、 The house may be apart

C、 There may not be any pressure inside the building

A.orange juice

B.cold coffee

C.hot coffee

D.champagne

Steam smoke will occur when ______.

A.extremely cold air from shore passes over warmer water

B.warm dry air from shore passes over cooler water

C.cold ocean water evaporates into warm air

D.cool rain passes through a warm air mass

A.In need of

B.In case of

C.In spite of

D.In charge of

What will be the benefit if the research on smart windows turns out to be successful, according to the last paragraph?

A．The buildings will look different.

B．Windows can be as large as you want.

C．We may not need air conditioners any more.

D．They are less expensive than traditional windows.

Man has always wanted to fly.Even as long as eight hundred years ago, an Englishman had tried.He made a (1)of wings from chicken feathers and fixed them to his shoulders.Then he jumped om a tall building.As you can imagine, he did not fly very far.(2) he fell to the ground and broke several bones.The first real attempt at flying took place in France in 1783.The two Mongolian brothers knew that hot air rose.If they could

fill a large balloon(3)hot air, they thought it would rise into the air and fly.They were right.They made a very large hot air balloon of cloth and paper.It measured ten meters it diameter.They filled it with hot air and the balloon got two hundred meters into the air.It fell into earth about three kilometers away.

At the next attempt, they (4) passengers use a bal loon to rise into the air and fly.We do not know what the passengers fell about the trip as they were a cock, a duck, and a sheep But we (5) know that the trip lasted eight minutes and the animals landed safely.(完型填空)

A.Instead

B.Pair

C.Do

D.Arranged

E.With

A.in addition

B.in addition to

C.additional

D.adding

If a diesel engine turned over freely but failed to start, the cause could be ________.

A.water in the fuel

B.cold lube oil

C.excessive starting air pressure

D.excessive fuel pressure

Hygroscopic cargoes should be ventilated when ______.

A.going from a warm to a cold climate

B.the dew point of the outside air is greater than the dew point of the air in the hold

C.the dew point of the air in the hold is very low

D.the outside dew point is 16°C and the cargo temperature is 12°C