A dry-steam reservoir produces steam with _____.
A.the energy to turn a turbine
B.impermeable rock
C.one or two separators
D.turbine operator
E.little or no water
F.hot springs

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• Alot of people could fall ill after drinking contaminated water.
  A:muddled
  B:polluted
  C:mixed
  D:troubled

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  Black Holes
  1 Black holes can be best described as a sort of vacuum,sucking up everything in space.Scientists
  have discovered that black holes come from an explosion of huge stars.Stars that are near death can no longer
  burn due to loss of fuel , and because its temperature can no longer control the gravitational（重力的）force,
  hydrogen ends up putting pressure onto the star's surface until it suddenly explodes then collapses.
  2 Black holes come from stars ihat are made of hydrogen,other gases and a few metals.When these
  explode it can turn into a stellar-mass（恒星质量) black hole , which can only occur if the star is large enough
  (should be bigger than the sun)for the explosion to break it into pieces,and the gravity starts to compact
  every piece into the tiniest particle.Try to see and compare:if a star that's ten times the size of the sun ends
  up being a black hole that's no longer than 70 kilometers,then the Earth would become a black hole that'S
  only a fraction of an inch!
  3 Objects that get sucked in a black hole will always remain there,never to break free.i1it remember
  that black holes can only gobble up（吞噬）objects within a specific distance to it.It's possible for a large
  star near the sun to become a black hole,but the sun will continue to stay in place.Orbits（轨道）do not
  change because the newly formed black hole contains exactly the same amount of mass as when it was a star,
  only this time its mass is totally contracted that it can end up as no bigger than a state.
  4 Sofar,astronomers have figured out that black holes exist because of Albert Einstcin's theory of
  relativity.In the end,through numerous studies,they have discovered that black holes truly exist.Since black
  holes trap light and do not give off light,it is nearly impossible to detect black holes via a telescope.But
  astronomers continue to study galaxies（银河系）, space and the solar system to understand how black holes
  might evolve.It is possible that black holes can exist for millions of years,and later contribute to a bigger
  process in galaxies,which can eventually lead to creation of new entities（实体）.Scientists also credit black
  holes as helpful in learning how galaxies began to form.
  When a large star explodes,the gravity compacts every piece into______.
  A:the existence of black holes
  B:the creation of new entities
  C:the same amount of mass
  D:an fraction of an inch
  E:a fraction of an inch
  F:the tiniest particle

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  Obtaining Drinking Water from Air Humidity
  Not a plant to be seen,the desert ground is too dry.But the air contains water,and research scientists
  have found a. __________
  (51)of obtaining drinking water from air humidity."The process we have
  developed is based exclusively on renewable energy sources_________(52)thermal solar collectors and
  photovoltaic（光电的）cells , ________( 53 ) makes this method completely energy-autonomous. It will
  ____________( 54 ) function in regions where there is no electrical infrastructure（基础设施）,"says Siegfried
  Egner,head of the research team. The principle of the_________(55)is as follows:hygroscopic（吸湿的）
  brine（盐水）一saline（含盐的）solution which absorbs moisture一runs down a tower-shaped unit and absorbs
  water from the air. It is then sucked__________(56)a tank a few meters off the ground in which a vacuum
  prevails.Energy from solar collectors_________(57)up the brine,which is diluted by the water it has
  __________ (58).
  Because of the vacuum,the boiling point of the liquid is lower than it would be under__________(59)
  atmospheric pressure. The evaporated (蒸发的）, non-saline water is condensed and runs down through a
  completely filled tube in a controlled manner. The gravity of this water column_______(60)produces the
  vacuum and so a vacuum pump is not needed.The reconcentrated brine________(61)down the tower
  surface again to absorb moisture from the air.
  "The concept is suitable for various water________(62).Single一person units and plants
  supplying water to entire hotels are conceivable,"says Egner. Prototypes have been built for_______
  (63)system components一air moisture absorption and vacuum evaporation一and the research scientists
  have already __________(64)their interplay on a laboratory scale.In a further ________(65)the re-
  searchers intend to develop a demonstration facility.
  _________(60)
  A:continuously
  B:suddenly
  C:typically
  D:seriously

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  Computer Plug-in
  1.Life on the Internet can be enriched if you don't restrict yourself to just written words and still pictures.Even if you are a newcomer to the Internet world,you've probably heard about multi-media on-line一listening to radio,watching animations and videos,even playing in three-dimensional space.Sound and movement make information come alive.
  2.In order to experience that,some special pieces of software called plug-ins are necessary. The term"plug-in"refers to a small,add-on piece of software which extends the capabilities of your web browser,like Netscape Navigator or Microsoft Explorer,turning your computer into a radio or TV.
  3.When you open a web page with a file requiring a plug-in which you don't have.you will usually receive a message asking if you want to get it by downloading it and installing it into your computer. Most of the time,the installation will be automatic.
  4.Occasionally,you come across a downloaded file which needs to be decompressed or unzipped before installation.Once installed,plug-ins run automatically,without you having to do anything.
  5.Many multimedia controls still need to be obtained from the developer but are installed automatically.
  6.Shockwave is a typical example of it. All you need to do is go to the Macromedia site and click on the link to install the ActiveX control.The rest happens automatically.The next time you go to a"Shocked"website,the Shockwave control loads and plays the movie.
  7.Most plug-ins and controls can be downloaded for free on the Internet,although not all will work with every system.Some of them,for instance,only work with Windows 95.
  Paragranh 6_______
  A:Life online can be colorful.
  B:How plug-ins are installed.
  C:Plug-ins should not be absent if you want to enjoy the Internet.
  D:How Shockwave is installed and used.
  E:No money is charged for the use of plug-ins.
  F: The developer's permission is needed before you install a plug-in.

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  Working for Fun and Profit
  1.It's a sunny weekend morning. You decide to take a walk.Everything is quite except for a.group of people and some colorful objects you see about three blocks away.As you get closer,you notice that there are many things lying on the ground:some National Geographic magazines,a collection of toy trucks,some weight lifting equipment,two bicycles,and a set of chairs.People are parking cars,getting out,and looking over the objects in the driveway.You consider taking a detour around the group of people,but you are curious.Was there an accident?Is this a party?No!Welcome to your first garage sale!
  2.On the same morning,a friend of yours takes a drive.He makes a mistake at an intersection and takes a wrong turn.He passes a large parking lot full of people,not cars.He sees many multicolored objects.At first he thinks it's an art show. Then he decides it's a fair. He parks his car and gets out to explore.He's just arrived at his first flea market.
  3.Garage sales and flea market are popular in the United States.Many Americans find that they can make a little extra money and have fun being"weekend entrepreneurs”.They take outgrown clothing,appliances,toys,and books and resell them at garage sales and flea markets.
  4.Flea markets are generally open spaces in or out of town that become busy sales centers on weekends.People who want to sell new or used clothing,tools,furniture,or books rent a space for the day for a small amount of money and sell their merchandise.Shoppers from near and far come to get good buys on imported watches,house plants,magazines,microscopes,children's clothes,and handmade goods such as embroidered pillowcases or jewelry.Some shoppers even buy and sell antiques.They search flea markets for special treasures that they can resell in their own stores for lots of money.
  5.Garage sales are smaller than flea markets,and the merchandise consists mainly of household items.Dishes,pots and pans,coat hangers,and children's clothing are inexpensive and common at garage sales. People frequently have garage sales before they move and on weekends when the weather is nice.Sometimes several families gather their unwanted household goods and sell them together. More merchandise attracts more customers.
  6.Cleaning,organizing,pricing,and moving merchandise is hard work,but the popularity of flea market and garage sales proves that many Americans work for fun!
  People usually have garage sales after they move.
  A:Right
  B:Wrong
  C:Not mentioned

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