练习15：

public and private schools in the unite states

　　religious and private schools receive little or no support from public taxes in the unite states, and, as a result, are usually somewhat expensive to_1_. the largest group of religious schools in america _2_ by the roman catholic church. while religious schools tend to be_3_ expensive than private schools, there are usually some fees.
　　when there is free education available to all children in the unite states, why do people _4_ money on private schools? americans offer_5_ great variety of reasons for doing so, including the desire of some parents to _6_ their children to schools _7_ classes tend to be smaller, or where religious instruction is included as part of the educational program, or because, _8_ their opinion, the public schools in their area are not _9_ high enough quality to meet their needs. private schools in the unite states _10_ widely in size, quality, and in the kind of program that are offered to meet _11_ of certain students.
　　the degree _12_ american parents are active in their children’s schools is often _13_ to people of other countries. most schools have organizations _14_ of both parents and teachers, usually called p.t.a for parent-teacher-association. they meet together to _15_ various matters concerning the school. parents often give their time to help with classroom or after school activities.
1.a) go b) attend c) take part in d) enroll
2. a) were run b) run c) is run d) is running
3.a) less b) more c) rather d) much
4. a) spend b) pay c) cost d) take
5. a) a b) the c) some d) /
6 a) bring b) bringing c) send d) sending
7. a) which b) what c) in that d) where
8. a) to b) in c) on d) for
9. a) / b) in c) of d) on
10. a) differ b) varies c) extend d) differs
11. a) the needs b) the satisfaction c) needs d) need
12. a) on which b) to which c) which d) what
13. a) surprise b) surprised c) surprising d) striking
14. a) consisting b) comprising c) composing d) making up
15. a) talk to b) comment c) discuss d) exchange

key: bcaaa cdbca abcac

练习16：

　　in the american family the husband and wife usually share important decision making. when the children are old enough, they take part__1__.
　　foreigners are often surprised by the permissiveness of american parents. the old rule that "children should be seen and not heard" is rarely__2__, and children are often allowed to do what they wish without strict parental__3__. the father seldom expects his children to obey him__4__ question, and children are encouraged to be independent__5__ an early age. some people believe that american parents carry this freedom__6__ far. others think that a strong father image would not__7__ the american values of equality and independence. because americans emphasize the importance of independence, young people are expected to __8__ their parental families by the time they have__9__ their late teens or early twenties.__10__, not to do so is often regarded as a failure, a kind of weak dependence.
　　this pattern of independence often results in serious__11__ for the aging parents of a small family. the average american is expected to live __12__ the age of 70. the job-retirement age is __13__ 65. the children have left home, married, and __!4__ their own households. at least 20 percent of all people over 65 do not have enough retirement incomes.__15__ the major problem of many elderly couples is not economic. they feel useless and lonely with neither an occupation nor a close family group.

1.a) either b) though c) as well d) also
2.a) discussed b) followed c) seen d) heard
3. a) control b) support c) agreement d) criticism
4. a) for b) on c) without d) in
5. a) in b) at c) on d) for
6. a) too b) almost c) nearly d) quite
7. a) fit b) meet c) suit d) satisfy
8. a) break up b) break into c) break through d) break away from
9.a) reached b) come c) arrived d) d) developed
10.a) in truth b) in name c) indeed d) in a word
11.a) questions b) problems c) matters d) affairs
12.a) on b) up c) from d) beyond
13.a) only b) usually c) sometimes d) seldom
14.a) set forth b) set aside c) set up d) set down
15.a) but b) therefore c) in contrast d) on the other hand

key: cbacb acdac bdbca

　in the american family the husband and wife usually share important decision making. when the children are old enough, they take part__1__.
　　foreigners are often surprised by the permissiveness of american parents. the old rule that "children should be seen and not heard" is rarely__2__, and children are often allowed to do what they wish without strict parental__3__. the father seldom expects his children to obey him__4__ question, and children are encouraged to be independent__5__ an early age. some people believe that american parents carry this freedom__6__ far. others think that a strong father image would not__7__ the american values of equality and independence. because americans emphasize the importance of independence, young people are expected to __8__ their parental families by the time they have__9__ their late teens or early twenties.__10__, not to do so is often regarded as a failure, a kind of weak dependence.
　　this pattern of independence often results in serious__11__ for the aging parents of a small family. the average american is expected to live __12__ the age of 70. the job-retirement age is __13__ 65. the children have left home, married, and __!4__ their own households. at least 20 percent of all people over 65 do not have enough retirement incomes.__15__ the major problem of many elderly couples is not economic. they feel useless and lonely with neither an occupation nor a close family group.

1.a) either b) though c) as well d) also
2.a) discussed b) followed c) seen d) heard
3. a) control b) support c) agreement d) criticism
4. a) for b) on c) without d) in
5. a) in b) at c) on d) for
6. a) too b) almost c) nearly d) quite
7. a) fit b) meet c) suit d) satisfy
8. a) break up b) break into c) break through d) break away from
9.a) reached b) come c) arrived d) d) developed
10.a) in truth b) in name c) indeed d) in a word
11.a) questions b) problems c) matters d) affairs
12.a) on b) up c) from d) beyond
13.a) only b) usually c) sometimes d) seldom
14.a) set forth b) set aside c) set up d) set down
15.a) but b) therefore c) in contrast d) on the other hand

key: cbacb acdac bdbca

练习17：

water

　　from the beginning, water has furnished man with a source of food and a highway to travel upon. the first __1__ arose where water was a dominant element in the environment, a challenge to man’s ingenuity. the egyptians invented the 365-day calendar __2__ the nile’s annual flooding. the babylonians, who were among the most famous law-makers in ancient times, invented laws __3__ water usage. water inspired the chinese to build a 1,000-__4__ canal, a complex system which, after nearly 2,500 years, remains still practically __5__ and still commands the astonishment of engineer. but the __6__ never found complete solutions to their water problems. the yellow river is also known __7__ "china’s sorrow"; it is so unpredictable and dangerous __8__ in a single flood it has caused a million __9__. floods slowed the great civilization of the indus river valley, and inadequate drainage ruined __10__ of its land. today water dominates __11__ as it always has done. its presence continues to __12__ the location of his homes and cities; its violent variability can __13__ man of his herds or his crops; its routes links him __14__ his fellows; its immense value may __15__ to already dangerous political conflicts. there are many examples of his in our own time.

1. a) governments b) cultures c) civilizations d) universities
2. a) in regard to b) in response to c) in case d) in spite of
3. a) regulates b) regulate c) regulated d) regulating
4. a) miles b) mile c) mile’s d) miles’
5. a) in use b) for use c) by use d) on use
6. a)villagers b) ancients c) farmers d) merchants
7. a) for b) by c) to d) as
8. a) that b) when c) because d) which
9. a) injuries b) deaths c) damages d) ruins
10. a) a number of b) a couple of c) many of d) much of
11. a) woman b) women c) man d) men
12. a) govern b) control c) lead d) change
13. a) move b) violate c) kill d) disappear
14. a) by b) on c) and d) to
15. a) increase b) add c) expand d) extend

keys: cbdba bdabd cacdb

the development of rubber
　　here is the story of rubber. from the earliest time it was __1__ common knowledge to the peruvians that when a cut
was made in the outside skin of a rubber tree, a white liquid __2__ milk came out, and that __3__ this a sticky mass of
 rubber might be made. this rubber is soft when warm, so that it is possible to give it any __4__. the peruvians made
 the discovery that it was very good for keeping out __5__. then in the early 1800’, the americans made use of it for
the first time. first they made overshoes __6__ their feet dry. then came a certain mr. mackintosh, who made coats of
 cloth covered with natural rubber. from that day to this we have been coating cloth with rubber as mr. mackintosh
__7__, and our raincoats are still named after him.
　　but these first rubber overshoes and raincoats were all soft and sticky in summer, and __8__ and inelastic in the winter
 when it was cold. but the rubber we have today is soft and elastic, though very strong--- ven in the __9__ summer and the coldest winter. this was made __10__ by a man called goodyear. __11__
experiments, he found that nitric acid (hno3) made the rubber much better, but it is not hard and strong enough.
then strange thing took place. a friend of __12__, nicholas hayward, had the idea in his sleep that rubber might be
made hard and strong if mixed with sulphur and put in the sun. goodyear put this idea __13__ the test, and saw that
it did have more or less the desired effect---
though somewhat less than more. the only effect it had was on the outside of the rubber. it is common knowledge
now that the way to make rubber hard and strong is __14__ sulphur. it took goodyear four more years to find this
 method. when at last he did it, he had nothing at all. everything of the smallest value __15__ to get money, even his
 sons’ school-books. 
1. a) a 
　b) \
　c) an
　d) the
2. a) like
　b) alike
　c) in the form of
　d) similar
3. a) with
　b) from
　c) up
　d) of
4. a) thing
　b) heat
　c) press
　d) form
5. a) wet weather
　b) wet day
　c) the wet
　d) wet
6. a) to make
　b) to keep
　c) make
　d) keep
7. a) did
　b) had done
　c) has done
　d) was doing
8. a) cold
　b) cool
　c) hard
　d) strong
9. a) warmer
　b) warm
　c) warmest
　d) warm-up
10. a) impossible
　b) possibly
　c) possibility
　d) possible
11. a) after many
　b) with an
　c) having made much
　d) with regard to
12. a) him
　b) his
　c) them
　d) theirs
13. a) on
　b) to
　c) in
　d) with
14. a) to heat with
　b) to heat it by
　c) by heating it with
　d) by heating with
15. a) was used
　b) had used
　c) had been used
　d) was being used
key: babdc baccd abbcc