Why can not the electric eel produce electricity for very long？

回答题：

Looking to help the environment？ Consider the following simple ideas.

Turn off electrical devices when they"re not being used.

Turning off， rather than leaving on stand-by， things like your TV and computer will save huge amounts of energy. With this， we can all help reduce the amount of carbon dioxide emitted into the earth"s atmosphere， thereby reducing pollution and global warming.

Share your ear.

Rather than traveling to work alone， why not arrange ear-sharing with one or more of your，friends or colleagues？ To give you an example， if you drive a fashionable ear， you will use more energy in a year than you would leaving your fridge open for seven years， or your TV on for thirty-two years ! Imagine the savings if you shared your ear with 2，3 or even 4 other people !

Refuse junk mail.

While we all complain about how much junk mail we get， we very rarely do anything about it. The mail continues to go straight from our letter-boxes into the garbage bin——with 99% of it not even opened. What can you do about this？ There are various websites where you can register to receive no junk mail. As well as saving time， you"ll also be doing a lot for the environment. Each year，100 million trees are used to produce junk mail.250，000 homes could be heated with one day"s supply of junk mail.

There are many other everyday changes you can make to help the environment. They will cost you nothing， and many will actually save you money! Why not give it a try？ We can all help，if we really want to.

By turning off a TV or computer that‘s not being used，you will save a lot of energy. 查看材料

A.Right

B.Wrong

C.Not mentioned

听力原文： Villages in developing countries often lack many things--books, clean water, electricity. These shortages are easy to see. But a different kind of shortage is not easy to see. That is a shortage of experts. Many villages have no doctors, engineers or scientists. They have no one who knows how to treat unusual medical problems or design a new expert system. There's a way to ease these problems. They can do it with computers. In the past few years, computer scientists around the world have developed what they call expert systems. An expert system is a special kind of computer program. In some situations, it can take the place of a human expert. For example, an expert in medical system can help care for a sick person. A question appears on the computer screen, "Is the person hot？" You tell the computer either yes or no. The computer asks other questions. "Has the person lost any blood？" "Can the person move normally？" You answer. The computer continues to ask questions until it has enough information to make a decision. Then it tells what medicine or other treatment is needed. In this way the expert system takes the place of a doctor. Another kind of expert system takes the place of an engineer. It measures the flow of water in a river. It tells if a dam can be built on the river. It also tells how much electricity can be produced. Still other kinds of expert systems help solve problems for farmers and owners of small businesses.

(23)

A．Lack of electricity.

B．Shortage of books.

C．Lack of clean water.

D．Shortage of experts.

our choices markedA，B，C andD．Choose the one that is most suitable and mark your answerByBlacken-ing the corresponding letter on ANSWER SHEET I． Research shows thatBy using computers，studentsBecomeBetter problem solvers andBet—ter communicators．Over a network，using ___21___ and sharing flies，students have the chanceto collaborate and work ___22___ with other classmates，peers，and teachers．Networking elec—tronically can 23 learners create，analyze，and produce information and ideas more24 and efficiently．Networking people“put the inspiring and usable set of tools ___25___reach of the mass of computer ___26___ ，empowering them to___27___ Beyond simply processinginformation toDesign，publish，and express”(Mello，1996)．Through this ___28___electronicaccess to the world around them，students’social awareness and ___29___ increase．Networking___30___them from the limitations of ___31___writing tools that often inhibit and restrict writingprocesses．Learning is then___32___from a traditional passive—listening exercise to an experi-ence ofDiscovery，exploration，and excitement．Students canBegin to ___33___ their full poten—tial when __34__ are empowered to contribute and collaborate as a team to accomplish theirwriting tasks 35 effectively． （）

A.1etter

B.e-mail

C.book

D.message

Why can't you stop your （eternal） complaining？

A．long

B．everlasting

C．temporary

D．boring

听力原文： Villages in developing countries often lack many things. Books, clean water, electricity. These shortages are easy to see. But a different kind of shortage is not easy to see. That is a shortage of experts. Many villages have no doctors, engineers or scientists. They have no one who knows how to treat unusual medical problems or design a new energy system. Them' s a way to ease these problems. They can de it with computers. In the past few years, computer scientists around the world have developed what they call expert systems. An expert system is a special kind of computer program. In some situations, it can take the place of a human expert. For example, an expert in medical system can help care for a sick person. A question appears on the computer screen, "Is the person hot？" You tell the computer either yes or no. The computer asks other questions. "Has the person lest any blood？" "Can the person move normally？" You answer. The computer continues to ask questions until it has enough information to make a decision. Then it tells what medicine or other treatment is needed. In this way the ex pert system takes the place of a doctor. Another kind of expert system takes the place of an engineer. It measures the flow of water in a river. It tells if a dam can be built on the river. It also tells how much electricity can be produced. Still other kinds of expert systems help solve problems for farmers and owners of small businesses.

(30)

A．Lack of electricity.

B．Shortage of books.

C．Lack of clean water.

D．Shortage of experts.

A.whether

B.that

C.why

D.what

Why is music important？

A．It can arouse excitement

B．It can help to slow down body rhythms

C．It can make people eager to study

D．It makes people used to the passive learning