Lead deposits, which accumulated in soil and snow during the 1960’s and 70’s, were primarily the result of leaded gasoline emissions originating in the United States. In the twenty years that the Clean Air Act has mandated unleaded gas use in the United States, the lead accumulation worldwide has decreased significantly.

A study published recently in the journal Nature shows that air-borne leaded gas emissions from the United States were the leading contributor to the high concentration of lead in the snow in Greenland. The new study is a result of the continued research led by Dr. Charles Boutron, an expert on the impact of heavy metals on the environment at the National Center for Scientific Research in France. A study by Dr. Boutron published in 1991 showed that lead levels in arctic snow were declining.

In his new study, Dr. Boutron found the ratios of the different forms of lead in the leaded gasoline used in the United States were different from the ratios of European, Asian and Canadian gasolines and thus enabled scientists to differentiate (区分) the lead sources. The dominant lead ratio found in Greenland snow matched that found in gasoline from the United States.

In a study published in the journal Ambio, scientists found that lead levels in soil in the Northeastern United States had decreased markedly since the introduction of unleaded gasoline.

Many scientists had believed that the lead would stay in soil and snow for a longer period.

The authors of the Ambio study examined samples of the upper layers of soil taken from the same sites of 30 forest floors in New England, New York and Pennsylvania in 1980 and in 1990. The forest environment processed and redistributed the lead faster than the scientists had expected.

Scientists say both studies demonstrate that certain parts of the ecosystem respond rapidly to reductions in atmospheric pollution, but that these findings should not be used as a license to pollute.

57.　 The study published in the journal Nature indicates that ________.

A.　 the Clean Air Act has not produced the desired results

B.　 lead deposits in arctic snow are on the increase

C.　 lead will stay in soil and snow longer than expected

D.　 the US is the major source of lead pollution in arctic snow

58.　 Lead accumulation worldwide decreased significantly after the use of unleaded gas in the US　 _____ .

A.　 was discouraged B.　 was enforced by law

C.　 was prohibited by law　　　　　 D.　 was introduced

59.　 How did scientists discover the source of lead pollution in Greenland?

A.　 By analyzing the data published in journals like Nature and Ambio.

B.　 By observing the lead accumulations in different parts of the arctic area..

C.　 By studying the chemical elements of soil and snow in Northeastern America.

D.　 By comparing the chemical compositions of leaded gasoline used in various countries.

60.　 The authors of the Ambio study have found that ________.

A.　 forests get rid of lead pollution faster than expected

B.　 lead accumulations in forests are more difficult to deal with

C.　 lead deposits are widely distributed in the forests of the US

D.　 the upper layers of soil in forests are easily polluted by lead emissions

　 Most American students go to traditional (传统的) public schools. There are about 88, 000 public schools all over the US. Some students attend charter schools.

　　　 Charter schools are self-governing. Certain companies operate (经营) some charter schools. They are similar in some ways to traditional public schools. They receive tax money just as other public schools do. Charter schools must prove to local or state governments that their students are learning. These governments provide the schools with the agreement called a charter that permits them to operate.

　　　 Charter schools are different because they do not have to obey most laws that govern traditional public schools. Each school can choose its own goals and decide what to teach and how to teach them in their own way. Class size is usually smaller than in traditional public schools.

　　　 The government strongly supports charter schools as a way to re-organize public schools, which are failing to educate students. But some education unions are against charter schools. One teachers’ union has just released the results of the first national study, which compared the progress of students in both traditional schools and charter schools.

　　　 The results of the study show that charter school students performed worse on math and reading tests than the students in traditional public schools.

　　　 Some experts say the study is not fair because students in charter schools have more problems than students in traditional schools. Other education experts say the study results would make charter school officials realize that they should help their students make greater progress.

67. If a company wants to operate a charter school, it must ______.

　 A. try new methods of teaching B. prove its management ability

　 C. obey the local and state laws　　　 　　　　　　　 D. get the government’s permission

68. What’ s the government’ s attitude toward charter schools?

　 A. Doubtful. B. Supportive. C. Satisfied. 　 D. Unclear.

69. What can we learn from the text?

　 A. More students choose to attend charter schools.

　 B. Charter schools are better than traditional schools.

　 C. Students in charter schools are well educated.

　 D. People have different opinions about charter schools.

70. What might be the best title for the text?

　 A. Charter schools in America

　 B. Public schools in America

　 C. Schools in America

　 D. Education in America

Spending as little as $5 a day on someone else could significantly boost happiness, the team at the University of British Columbia and Harvard Business School found on Thursday.
Their experiments on more than 630 Americans showed they were measurably happier when they spent money on others—even if they thought spending the money on themselves would make them happier.
“We wanted to test our theory that how people spend their money is at least as important as how much money they earn,” said Elizabeth Dunn, a psychologist at the University of British Columbia. They asked their 600 volunteers first to rate their general happiness, report their annual (yearly) income and detail their monthly spending including bills, gifts for themselves, girls for others and donations to charity.
“Regardless of how much income each person made, those who spent money on others reported greater happiness, while those who spent more on themselves did not,” Dunn said in a statement.
Dunn’s team also surveyed 16 employees at a company in Boston before and after they received an annual profit-sharing bonus of between $3,000 and $8,000. “Employees who devoted more of their bonus to pro-social spending experienced greater happiness after receiving the bonus and the manner in which they spent that bonus was a more important predictor of their happiness than the size of the bonus itself” they wrote in their report, published in the journal Science.
　　They gave their volunteers $5 or $20 and half got clear instructions on how to spend it. Those who spent the money on someone or something else reported feeling happier about it.
“These findings suggest that very minor alterations (changes) in spending allocations (shares)—as little as $5—may be enough to produce real gains in happiness on a given day，”Dunn said.
60. What is the general idea of the passage?
A. The more you earn, the greater happiness you will get.
B. Spending more money on yourself will make you happier.
C. Money can buy happiness, but only if you spend it on someone else.
D. You can spend only 5$ a day to get happiness.
61. The underlined word “boost” in the first paragraph probably means_______.
A. help to find     B. help to bring    C. help to increase     D. help to get
62. Which of the following statements is NOT true according to the passage?
A. Those who spend more money on others can get much more bonus.
B. People usually think spending money on themselves will make them happier.
C. Very small changes in spending your money may be enough to gain happiness.
D. Researchers think that how people spend their money is at least as important as how much money they earn.
63. It can be inferred from the 6th paragraph that ______.
A. the volunteers not given 5$ or 20$ spent their own money on themselves.
B. those who spent the money on someone or something else felt happier about it.
C. the volunteers were given 5$ or 20$ as a reward for the experiment.
D. half of the volunteers could spend the money as they liked.

Mrs. White was a wealthy lady. She lived 　36　 in a large comfortable house where her children and grandchildren came to visit her frequently. However, she was　37　. She spent a lot of time thinking about her  38  and about her dead husband. Her children   39 about her and asked Dr. Green to see her.
Mrs. Green was an experienced doctor. She knew old people became upset in their ways and didn’t like to   40  what to do. She decided to get to know Mrs. White before she said anything. During the visit, Dr. Green asked Mrs White to give her a   41  of the house. Mrs. White was  42   her house and happily agreed. As they walked from room to room, Dr. Green   43  that there were a lot of violets (紫罗兰) in every window. She asked, “__44 _ do you have so many violets?” Mrs White replied, “ I love these   45  and they  46  so fast that I have more and more. When the tour of the house was over, Dr. Green said, “I have one suggestion to make. Whenever you   47 a friend or a neighbor that is   48 in bed or getting married, give 49  one of your violets.”
Mrs White said   50   about the doctor’s advice and for a few months    51 her visit, she didn’t give away any of her violets. Then one day she was invited to the   52  of her neighbor's daughter. She put a ribbon(丝带) on one of her potted plants and took it to the party. Later one of her friends was sick so she took a violet plant and took it to the hospital.  53    she began to give more and more of her potted violets to her neighbors. Over the years she  54 so many that she became known as the “  55  lady”.