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

A new plan for getting children to and from school is being started by a local government in Eastern England. This could end the worries of many parents fearful for their children’s safety on the roads.

Until now the local government has only been prepared to provide bus services for children living more than three miles from their school, or sometimes less if special reasons existed. Now it has been decided that if a group of parents ask for help in organizing transport they will be prepared to go ahead, as long as the arrangement will not lose money and children taking part will be attending their nearest school.

The new plan is to be fired out this term for children living at Milton who attend Impington School. The children live just within the three-mile limit and the local government said in the past that they would not undertake to provide free transport to the school. But now they have agreed to offer a sum of money for a bus service from Milton to Impington and back, a plan which has the support of the school’s headmaster. Between 50 and 60 parents have said they would like their children to take part. Final calculations have still to be carried out, but a government official has said the cost to parents should be less than ￡20 a term. They have been able to arrange the service at a low cost because there is already an agreement with the bus company for a bus to take children who live further away to Impington. The same bus would now just make one more journey to pick up the Milton children. The official said they would get in touch with other groups of parents who in the past had asked if transport could be provided for their children, to see if they would like to take part in the new plan.

1. What is the aim of the plan?

A.　 To prevent the students’ road accidents　 B.To relieve the traffic pressure

C.　 To save time for the parents and students　 D.To help the parents save money

2. How can the local government arrange the new bus service at a low cost?

A.　 By letting the bus run in the morning only

B.　 By limiting the number of the students

C.　 By getting the support from the headmaster

D.　 By linking the new bus service with the existing one

3. Which of the following is possible if the plan is carried out?

A.　 The bus company will make much more money

B.　 The children can choose whatever school they like

C.　 The parents can get rid of their worries

D.　 The students in Impington School can have free bus rides

4 This passage is most probably _____

A.　 a personal letter B. an advertisement C. a headmaster’s report D. a newspaper article

 

In the 1950s, a family that owned a farm near Beulah, Michigan kept a bull chained to an elm (榆树). The bull paced around the tree, dragging the heavy iron chain, which led to a groove (槽) in the bark . The groove deepened over the years. Though for whatever reason, it did not kill the tree.

   After some years, the family took their bull away. They cut the chain, leaving the loop around the tree and one link hanging down.

   Then one year, agricultural disaster struck Michigan in the form of Dutch Elm Disease. All of the elms lining the road leading to the farm became infected and died. Everyone thought that the old elm would be the next.

The farm owners considered doing the safe thing: pulling it out and cutting it up into firewood before it died. But they simply could not bring themselves to do it. It was as if the old tree had become a family friend. So they decided to let nature take its course.

   Amazingly, the tree did not die. Nobody could understand why it was the only elm still standing in the county!

Plant experts from Michigan State University came out to observe the tree. They observed the scar left by the iron chain, now almost completely covered by bark. The experts decided that it was the chain that saved the elm’s life. They reasoned that the tree must have absorbed so much iron from the chain that it became immune to the virus.

　It’s said that what doesn’t kill you will make you stronger. Or, as Earnest Hemingway put it, "Life breaks us all, but afterwards, many of us are strongest at the broken places."

1.What did the family do with the elm when the agricultural disaster hit Michigan one year?

A. They invited plant experts to observe it.

B. They pulled it out and chopped it up into firewood.

C. They prevented it from being infected by the disease.

D. They did nothing and just let it be.

2.Which of the following statements is TRUE?

A. A groove formed because of natural forces.

B. The family decided to keep the tree because they had become attached to it.

C. All of the elms in Beulah, Michigan died of the disease.

D. The plant experts advised the family to chop it down.

3.What actually saved the elm?

A. The bull.   B. The groove.    C. The iron chain.  D. The experts.

4.What would be the best title for the passage?

A. Let nature take its course

B. Strengthened by our wounds

C. Constant dripping wears away a stone

D. Bend, but don’t break

 

I  　grandfather’s diary in the attic.

A.came to　　　　　B.came by　　　　C.came at　　　　D.came across

　More surprising, perhaps, than the current difficulties of traditional marriage is the fact that marriage itself is alive and thriving（旺盛的）. As Skolnich notes, Americans are a marrying people: relative to Europeans, more of us marry and we marry at a younger age. Moreover, after a decline（衰退）in the early 1970s, the rate of marriage in the United States is now increasing. Even the divorce（离婚）rate needs to be taken in this pro- marriage context: some 80 percent of divorced individuals remarry. Thus, marriage remains by far the preferred way of life for the vast majority of the people in our society.

　　What has changed more than marriage is the nuclear family. Twenty- five years ago, the typical American family consisted of the husband, the wife, and two or three children. Now, there are many marriages in which couples have decided not to have any children, and there are many marriages where at least some of the children are from the wife’s previous marriage, or the husband’s, or both. Sometimes these children spend all of their time with one parent from the former marriage; sometimes they are shared between the two former spouses （配偶）．

　　Thus, one can find every type of tamely arrangement. There are marriages without children; marriages with children from only the present marriages; marriages with “full - time” children from both the present and former marriages; marriages with“full- time”children from the present marriage and“ part- time”children from former marriages. There are stepfathers, stepmothers, half- brothers and half - sisters. It is not all that unusual for a child to have four parents and eight grandparents! These are enormous changes from the traditional nuclear family. But even so, even in the midst of all this, there remains one constant: most Americans spend most of their adult lives married.

　By calling Americans a marrying people the writer means that ________.

　　A. Americans are more traditional than Europeans

　　B. Americans expect more out of marriage than Europeans

　　C. there are more married couples in the USA than in Europe

　　D. more of Americans, as compared with Europeans, prefer marriage and they accept it at a younger age

Divorced Americans ________ .

　　A. prefer the way they live

　　B. will most likely remarry

　　C. have lost interest in marriage

　　D. are the majority of people in the society

Which of the following can be presented as the picture of today’s American families？

　　A. Which types of family arrangements have become socially acceptable.

　　B. A typical American family consists of only a husband and a wife.

　　C. Americans prefer to have more kids than before.

　　D. There are no nuclear families any more.