A dam is a man-made structure built across a river. Most dams are built to control a river’s water flow, improve navigation and control flooding. However, some dams are built to produce hydro-electric power.

Hydro-electric power is produced as water passes through a dam, and into a river below. The more water that passes through a dam, the more energy is produced. Once a dam is built, a man-made lake is created behind the dam.

Electricity is produced by a kind of equipment called a turbine(水轮机). Turbines contain metal coils(线圈) surrounded by magnets(磁铁). When the magnets move round rapidly over the metal coils, electricity is produced. Turbines are located inside dams. The falling water makes the magnets go around the coils.

Dams provide clean energy, but they can also harm the environment. Species that use rivers to reproduce are often hurt by dams. In the Northwest of the US, the population of fishes has dropped from 16 million to 2.5 million since hydro-electric plants were built on the Columbia River. Dams all over the world have hurt some species. 

  The highest dam in the Unites States is located near Oroville, California. The Oroville Dam towers 230 meters and is more than a mile wide. This dam was built in 1968, 22 years after the Hoover Dam. The Hoover Dam, on the Nevada-Arizona border controls the Colorado river. It is 221 meters high and has 2.6 million hectare-meters of water.

The highest dam in the world is the Nurek Dam on the Vakhsh River in Tadzikistan, a country in central Asia. This dam is 300 meters tall. 

Which of the following statements is NOT true according to the passage?              

A. Some dams are built for controlling a river’s water flow.

B. Hydro-electric power is usually produced through a dam.

C. Dams can offer energy and they are harmless to the environment.

D. Generally speaking, where there is a dam, there is a man-made lake.

The third paragraph mainly tells us _____.                          

  A. how hydro-electric power is produced

  B. What a turbine is and how it works 

  C. how the magnets and the metal coils work

  D. how the falling water passes through a turbine                     

The dam which controls the Colorado river is ____.                  

A. the Oroville Dam  B. the Hoover Dam  C. the Nurek Dam  D. the Vakhsh Dam

A dam is a man-made structure built across a river. Most dams are built to control a river’s water flow, improve navigation and control flooding. However, some dams are built to produce hydro-electric power.

Hydro-electric power is produced as water passes through a dam, and into a river below. The more water that passes through a dam, the more energy is produced. Once a dam is built, a man-made lake is created behind the dam.

Electricity is produced by a kind of equipment called a turbine(水轮机). Turbines contain metal coils(线圈) surrounded by magnets(磁铁). When the magnets move round rapidly over the metal coils, electricity is produced. Turbines are located inside dams. The falling water makes the magnets go around the coils.

Dams provide clean energy, but they can also harm the environment. Species that use rivers to reproduce are often hurt by dams. In the Northwest of the US, the population of fishes has dropped from 16 million to 2.5 million since hydro-electric plants were built on the Columbia River. Dams all over the world have hurt some species. 

  The highest dam in the Unites States is located near Oroville, California. The Oroville Dam towers 230 meters and is more than a mile wide. This dam was built in 1968, 22 years after the Hoover Dam. The Hoover Dam, on the Nevada-Arizona border controls the Colorado river. It is 221 meters high and has 2.6 million hectare-meters of water.

The highest dam in the world is the Nurek Dam on the Vakhsh River in Tadzikistan, a country in central Asia. This dam is 300 meters tall. 

Which of the following statements is NOT true according to the passage?              

A. Some dams are built for controlling a river’s water flow.

B. Hydro-electric power is usually produced through a dam.

C. Dams can offer energy and they are harmless to the environment.

D. Generally speaking, where there is a dam, there is a man-made lake.

The third paragraph mainly tells us _____.       56-60 ADB                    

  A. how hydro-electric power is produced

  B. What a turbine is and how it works 

  C. how the magnets and the metal coils work

  D. how the falling water passes through a turbine                     

The dam which controls the Colorado river is ____.                  

A. the Oroville Dam  B. the Hoover Dam  C. the Nurek Dam  D. the Vakhsh Dam

I have a special rule for travel: never carry a map. Sometimes I get lost, but I usually have a good time. I can practice a new language, meet new people, and learn new customs. And I find out about different “styles” of directions every time I ask, “ How can I get to the post office?”

    In Japan, most streets don’t have names; people use landmarks in their  directions. For example, the Japanese will say to the travelers “Go straight down to the corner. Turn left at the big hotel and go past a market. The post office is across from the bus stop.”

    In the countryside of the American Midwest, there are not mountains, so the land is very flat (平的)，in many places there are no towns or buildings within miles. Instead of landmarks, people will tell you directions and distances. For example, they will say: “Go north two miles. Turn east, and then go another mile.”

    People in Los Angeles, California, measure distance in time, not miles. “How far away is the post office?” you ask. “Oh”, they answer, “It’s about five minutes from here.” They don’t know how many miles away it is.

People in Greece sometimes do not even try to give directions because tourists seldom understand the Greek language. Instead, a Greek will often say, “Follow me.” Then he’ll lead you through the streets of the city to the post office.

66. The underlined word landmarks in the second paragraph means ____.

   A. easily recognizable (可辨认的) objects by which one can tell one’s position

   B. big markets where people can tell you how to get to the post office

   C. tall buildings in front of which is the post office

   D. bus stops which are near the post office you are looking for

67. From the passage we learn that in the American Midwest countryside, ____.

   A. there are no buildings                            B. there are no landmarks

   C. the fields are very flat                           D. there are some hills

68. Which of the following shows distance in time?

   A. The Japanese.                                  B. People in Los Angeles.

   C. People in Greece.                               D. People in the American Midwest.

69. Why don’t the Greeks try to give directions?

   A. Because they often say “Follow me.”

   B. Because they will lead you to the post office.

   C. Because they don’t understand any foreign language.

   D. Because tourists don’t understand their language.

70. The passage tells us that ____.

   A. there are different ways to get to the post office

   B. people everywhere can tell you how far the post office is

   C. in Greece there is much trouble in finding the post office

   D. there are different customs in different places

Recently, scientists have developed a wireless brainmachine interface that help restore communication to people who can no longer speak by reading brainwaves using electrodes(电极) stuck on their heads. Unfortunately, these have proved very slow, at roughly one word typed per minute, making normal conversations and social interactions virtually impossible.
Scientist Frank Guenther and his colleagues reveal a brainmachine interface that uses electrodes implanted directly into the brain for research into real time speech.
"It should soon be possible for extremely paralysed individuals who are incapable of speaking to produce speech through a laptop computer, " said Guenther.
The scientists worked with a 26-year- old male volunteer who experience near-total paralysis due to a stroke he suffered when he was 16. They implanted an electrode that had two wires into a part of the brain that help plan and execute movements related to speech. The electrode recorded brain signals when the volunteer attempted to talk and the wires spread them across the scalp(头皮)to help drive a speech synthesizer (合成器). The delay between brain activity and sound output was just 50 milliseconds on average, roughly the same with regular speech.
"He was quite excited, particularly on the first few days we used the system, as he got used to its properties, " Guenther recalled." I am sure the work proceeds slowly from his perspective, as it does from ours. Nonetheless, he was very excited about getting real-time audio feedback of his intended speech and happy to work very hard with us throughout the experiments."
"The current system uses data from just two wires. Within a year it will be possible to implant a system with 16 times as many." Guenther said." This will allow us to tap into neurons(神经元)，which in the end means better control over a synthesizer and thus better speech."
【小题1】In the study of Guenther, electrodes are _______.