51. What is this passage mainly about?

A. It’s mainly about the history of Stonehenge

B. It’s mainly about the building materials of Stonehenge.

C. It’s mainly about the new discoveries on Stonehenge.

D. It’s mainly about the inner structure of Stonehenge.

E

Priscilla Ouchida’s“energy-efficient”house turned out to be a horrible dream. When she and her engineer husband married a few years ago，they built a$1 00，000，three-bedroom home in California. Tightly sealed to prevent air leaks，the house was equipped with small double-pined(双层玻璃的)windows and several other energy-saving features. Problems began as soon as the couple moved in，however. Priscilla’s eyes burned. Her throat was constantly dry. She suffered from headaches and could hardly sleep. It was as though she had suddenly developed a strange illness.

Experts finally traced the cause of her illness. The level of formaldehyde(甲醛)gas in her 　kitchen was twice the maximum allowed by federal standards for chemical workers. The source of the gas? Her new kitchen cabinets and wall-to-wall carpeting.

The Ouchidas are victims of indoor air pollution，which is not given sufficient attention partly because of the nation’s drive to save energy. The problem itself isn’t new. “The indoor environment was dirty long before energy conservation came along，”says Moschandreas，a pollution scientist at Geomet Technologies in Maryland. “Energy conservation has tended to accentuate(强调)the situation in some cases. ”

The problem appears to be more troublesome in newly constructed homes rather than old ones. Back in the days when energy was cheap，home builders didn’t worry much about unsealed cracks. Because of such leaks. the air in an average home was replaced by fresh outdoor air about once an hour. As a result，the pollutants generated in most households seldom build up to dangerous levels.

50. The author probably thinks that　　　　　 .

A. Stonehenge was built for less than 1，000 years

B. Stonehenge was built for religious ceremonies

C. Stonehenge was built by hand alone

D. people celebrated their festivals in Stonehenge

49. Which of the fallowing is TRUE according to the second paragraph?

A. The stones lie flat on the ground，

B. 下he stones are various in the Stonehenge.

C. The stones in Stonehenge stand in a huge circle.

D. The standing stones have doors in them.

48. What was Stonehenge made of?

A. Bluestone. 　　　　　　　　　　　　　　　　　　　　　　　 B. Sandstone.

C. Sarsen. 　　　　　　　　　　　　　　　　　　　　　　　　　　　 D. Bluestone and sarsen

47. Pollution on cultivated land leads to the following outcomes EXCEPT　　　　 .

A. a threat to China’s food safety

B. worse water quality in rural areas

C. a variety of diseases

D. the sustainable development of agriculture

D

Stonehenge is the best known of a number of such ancient places in Britain. It stands on the flat，windy Salisbury Plain，heal‘the city of Salisbury, England. Early, Britons built Stonehenge from bluestone and a very hard sandstone called sarsen. Experts believe the builders of Stonehenge knew about design，engineering and sound. These ancient people did not have highly developed tools. But they built a huge monument of heavy stones.

Some of the monument’s standing stones have lintel(过梁)stones on top：The lintels lie flat on the standing stones. Most of the stones of Stonehenge stand in incomplete formations of circles. They differ in height. weight and surface texture(质地). One of the largest stories weighed about forty thousand kilograms. Some stones are more than seven meters high. Other broken stones lie on the ground.

Work on Stonehenge may have started as earl)'as five thousand years ago. Scientists believe it was completed over three periods lasting more than one thousand years. Archeologists have studied it for many years. For centuries，people have questioned the meaning of the stones.

Now, archeologists have discovered remains of an ancient village that may have been home to the workers who built Stonehenge. People from the village also may have used the huge monument for religious ceremonies. The discovery of the village helps confirm an important theory about Stonehenge.

The huge monument did not stand alone. Stonehenge may have been part of a larger religious complex(建筑群). 11he theory also proposes that people held events in the village mad at Stonehenge to celebrate the change of seasons and honor the dead.

The scientific process of radiocarbon dating found that the village is about four thousand six hundred years old. The archeologists believe the inner circle of Stonehenge was also built at about that time. The timing led them to believe that the people of the village could have built 　Stonehenge.

46. According to the passage，which of the following is NOT true?

A. China has about 10 million hectares of arable land

B. Only about 20 rural water supply stations passed checks for bacteria in China.

C. The unreasonable use of chemical fertilizer leads to farmland pollution

D. Large amounts of contaminants leads to worse water quality in rural areas

45. The underlined word“grave”in Paragraph 1 probably means

A. certain　　 　　　　　　　 B. serious　　 　　　　　　　 C. big　 　　　　　　　　　　 D. terrible

44. The author writes the passage to　　　　　　 .

A. 1et the readers examine their mistakes

B. present the readers a new idea

C. come up with a solution to ending farmland pollution

D. inform the readers of the importance of fighting farmland pollution

43. The best title for this passage might be　　　　　 .

A. Intelligence　　 　　　　　　　　　　　　　　　　　　　　　 B. Birth and Environment

C. The Answer to a Question　　　　　　 　　　 D. Why Are Some People Born Clever

C

At least 10 million hectares of cultivated(耕作)land in China are polluted, which makes a grave threat to the country’s food safety, the Xinhua News Agency reported on Friday.

The polluted land，which is mostly in economically developed areas，accounts for one-tenth of the country’s total arable(可耕种的)land，according to an incomplete survey by the State Environmental Protection Administration，China’s top environment watchdog.

Pollution on cultivated land threatens the environment，food safety and the sustainable development of agriculture，the administration said.

Because of continual，too much use of chemical fertilizer, pesticide and agricultural plastic sheeting, as well as irrigation using polluted water, a large amount of contaminants(污染物)remain in the cultivated land.

The contaminants affect the soil’s ecological structure and function，leading to decreased soil productivity, lower crop yield(产量)，and lower quality of agricultural products-

It also leads to worse water quality in rural areas.

Less than 9 per cent of drinkable water passed checks for bacteria in243 rural water supply stations 　across the county.

Another survey, which took samples of drinking water and groundwater an 69 small towns。 in Beijing, Tianjin and Hebei Province of North，China, showed that more than half of the water contains too much nitrate(硝酸盐)，which may cause diabetes(糖尿病)and damage the kidney.

The administration estimated at least 1 90 million farmers are drinking water that contains harmful substances.

Many villagers drink unfiltered water taken from shallow water wells or water cellars， which are reported to have poor sanitary conditions·

42. The writer of this article believes that　　 .

A. the development of one’s intelligence is determined by many factors working together

B. environment plays the most important role in the development of intelligence

C. education plays the most important role in the development of intelligence

D. birth plays the most important role in the development of intelligence