Have you ever noticed the colour of the water in a river or stream after a heavy rainfall? What do you think caused this change in colour? It is soil that has been washed into the river from the riverbank or from t}le nearby fields．

Components of Soft

    Soil is made up of a number of layers(层)，each having its own distinctive colour and texture．The upper layer is known as the litter．It acts like a blanket．limiting temperature changes and reducing water loss．The topsoil layer is made up of small particles of rock mixed with rotten plant and animal matter called humus(腐殖质)，which is black and gives the topsoil its dark colour．This layer is usually rich in nutrients，oxygen，and water．Below the topsoil is the subsoil，a layer that contains more stones mixed with only small amounts of organic matter．This layer is lighter in colour because of the lack of humus．Beneath the soil lies a layer of bedrock．

    Soil forms from the bottom up．Over time bedrock is attacked by rain, wind，frost, and snow．It is gradually broken down into smaller particles in a process called weathering．Plants begin to grow，and rotten materials enrich the topsoil．Most of the soil in Eastern Canada．for example．Was formed from weathered rock that was exposed when the ice disappeared l2．000 years ag0．

Water Beneath the Soil

    Surface water collects and flows above the ground in lakes．ponds．and rivers．Once in the soil or rock，it is called groundwater．Gravity pulls groundwater through the soil in a process called percolation(渗透)．Eventually the water reaches a layer called the water table．Under this is bedrock through which water cannot percolate．

    As water percolates downward，it dissolves organic matter and minerals from the soil and carries them to deeper layers．This causes a serious problem because plants require these nutrients for growth.

Soil pH

    Soil can be acidic．neutral．or basic．The pH of the soil is determined by the nature of the rock

from which it was formed．and by the nature of t}le plants that grow and rot in it．

    The acidity of rain and snow can lower the pH of the groundwater that enters the soil．By burning fossil fuels such as coal，oil and gasoline，humans have been contributing to higher levels of acidity in many soils．When fossil fuels are burned．gases are released into the air and then fall back to earth as acid rain．Acid soil increases出e problem of carrying nutrients to lower soil levels．As nutrients are removed，soil is less fertile．Plants grow more slowly in acidic soil，and also become easily attacked by diseases．

67．The layer of soil that provides necessary nutrients for plant growth is called．

    A．1itter    B．topsoil    C．humus D．subsoil

68．According to the text．which of the following is NOT true?

    A．Soil forms from weathered rock on the earth surface．

  B．The deeper layer of soil is darker in colour than t}le surface soil．

  C．Air pollution is partially responsible for acid soil．

    D．Groundwater tends to carry away nutrients for plant growth．

69．We can infer from the passage that the water table lies       ．

A．between the topsoil layer and the subsoil layer

B．in the subsoil layer above bedrock

       C．between the subsoil layer and bedrock

       D．in the bedrock layer beneath the subsoil

70．The underlined word “dissolve” is used to express the idea that organic matter and minerals from soil are          ． 

    A．rushed away into the river

    B．cleaned and purified by water

    C．destroyed and carried away by water

    D．mixed with water and become part of it

Should struggling students be banned from clubs and sports?
Getting a bad grade in Rockingham, Vt. could get you kicked off the team! School officials there are considering k*s#5^unew guidelines that would prevent students with bad grades from participating in extracurricular activities, such as sports and clubs. The proposal would affect students in eighth grade and below.
School board member Mike says the policy would motivate students to work harder in school. He drafted a letter to coaches, parents, and after-school program leaders to encourage them to allow only kids who are meeting certain academic standards into their program.
Not everyone gives such policy an A+. Some people argue that no student should be excluded from after-school activities. They say taking part in extracurricular activities can help kids do better in class by improving their participation and concentration skills. They say a 2009 study from the Centers for Disease Control and Prevention found that time spent in extracurricular physical activities does not take away from students’ ability to do well in the classroom . In fact, it may even help boost girls’ academic performance.
Students themselves have different opinions.
SCHOOL COMES FIRST
Why not require good grades to participate in those activities?
Kids need to understand that grades are important. School comes first, period. Getting good grades help you with life, help you go to college, get a job, and so on. Banning underachieving students from extracurricular activities not only gives them motivation to get their grades up, but allows more time to study or get help from a tutor.
DON’T BAN STUDENTS
Every student should be able to participate in extracurricular activities, no matter what his or her grades are. Extracurricular activities can help kids concentrate more on doing homework. They can help kids develop mentally and physically.
A school policy that tells kids with bad grades that they can’t be in sports or the school play is like judging a book by its cover. Every student is unique. A kid may have a learning disability, an attention issue, or a difficult time studying in his or her home environment. His or her teachers should find why the student is struggling. Together they should find out a solution that will keep the student in the activity.
72. Which of the following is the closest in meaning to the underlined word “excluded”?
A. protected   B. approved C.  blamed   D. banned
73. What’s the author’s attitude to the policy that prevents students with bad grades from participating in extracurricular activities?
A. supportive   B. critical     C. neutral   D. indifferent
74. In the second paragraph “a 2009 study…”is used by the critics to        .
A. To indicate the author is against the policy.
B. To emphasize there is no need to ban the students with bad grades to take part in extracurricular activities.
C. To suggest girls can benefit from extracurricular activities.
D. To prove grades have nothing to do with extracurricular activities.
75. Some don’t think the policy is reasonable for the following reasons EXCEPT        .
A. Every kid is unique.
B. Extracurricular activities will benefit students mentally and physically.
C. . Grades will help students get a job.
D. One can learn more that can’t be learned in class.

—Where are Jack and Mike??

—They__________the furniture you asked for into the house.?

A.have been carrying                          B.carried?

C.have been carried                                   D.were carried

-- Why didn't Mike attend the evening party?

   -- He is a quiet boy; He loves reading at home ______ to parties.

   A. than go     B. rather than going        C. than going      D. more than goes

This year some twenty-three hundred teenagers(young people aged from13~19)from all over the world will spend about ten months in U.S. homes. They will attend U.S. schools, meet U.S. teenagers, and form impressions of the real America. At the same time, about thirteen hundred American teenagers will go to other countries to learn new languages and gain a new understanding of the rest of the world.
Here is a two-way student exchange in action. Fred, nineteen, spent last year in Germany with George’s family. In turn, George’s son Mike spent a year in Fred’s home in America.
Fred, a lively young man, knew little German when he arrived, but after two months’ study the language began to come to him. School was completely different from what he had expected—much harder. Students rose respectfully when the teacher entered the room. They took fourteen subjects instead of the six that are usual in the United States. There were almost no outside activities.
Family life, too, was different. The father’s word was law, and all activities were around the family rather than the individual(个人). Fred found the food too simple at first. Also, he missed having a car.
“Back home, you pick up some friends in a car and go out and have a good time. In Germany, you walk, but you soon learn to like it.”
At the same time, in America, Mike, a friendly German boy, was also forming his idea. “I suppose I should criticize(批评)American schools,” he said. “It is far too easy by our level. But I have to say that I like it very much. In    Germany we do nothing but study. Here we take part in many outside activities. I think that maybe your schools are better in training for citizens. There ought to be some middle ground between the two.”
【小题1】This year ________teenagers will take part in the exchange programme between America and other countries.