When prices are low, people will buy more, and when prices are high, they will buy __(1)__ (little).　 Every shopkeeper knows this. According to the economic point of view, changes in the prices of goods cause changes __(2)__ supply and demand.　 __(3)__ we all know, people buy fewer goods as the price goes __(4)__.　 On the contrary, a decrease in price causes __(5)__ increase in demand.

Business firms look for the perfect price at __(6)__ the largest profit can __(7)__ (make).　 In doing so, they must carry out a lot of research on the market to have an accurate estimation of the people’s demand and their __(8)__ (purchase) power so that they can produce the exact amount of goods and price __(9)__ goods properly.　 __(10)__ there will be no profit for them to make.

One topic is rarely mentioned in all the talk of improving standards in our schools: the almost complete failure of foreign-language teaching. As a French graduate who has taught for more than twenty-five years, I have some ___21_____ of why the failure is so total. 　22 　the faults already found out in the education system as a whole, there have been several serious 　23 　which have a direct effect on language teaching.

The first is the removal from the curriculum (课程) of the thorough teaching of English 　24­­­ . Pupils now do not know a verb from a noun or the subject of a sentence from its object.

Another important error is mixed-ability teaching, or teaching in ability groups so 　25 　that the most able groups are 　26 　and are bored while the least able are lost and 　27 　bored.

Progress depends on memory, and pupils start to forget immediately they stop having 28 　lessons. This is why many people who attended French lessons at school have forgotten it a few years later.

Most American schools have accepted what is necessary and 　29 　modern languages, even Spanish, from the curriculum. Perhaps it is time for Britain to do the same, and stop 30 　resources on a subject which few pupils want or need.

21. A. question　　　　 B. evidence　　　 C. idea　　　　　　 D. knowledge

22. A. Due to　　　　　　　　 B. In addition to　　　 C. Instead of　　　　　　 D. In spite of

23. A. errors　　　　　　　　　 B. situations　　　　　　 C. systems　　　　　　　 D. methods

24. A. vocabulary　　　　　 B. culture　　　　　　　　 C. grammar　　　　　　 D. sentences

25. A. wide　　　　　　　　　　 B. similar　　　　　　　　 C. separate　　　　　　　 D. unique

26. A. kept out　　　　　　　 B. turned down　　　　 C. held back　　　　　　 D. left behind

27. A. surprisingly　　　　　 B. individually　　　　　 C. equally　　　　　　　　 D. hardly

28. A. extra　　　　　　　　　　 B. traditional　　　　　　 C. basic　　　　　　　　　 D. regular

29. A. restored　　　　　　　 B. absorbed　　　　　　 C. prohibited　　　　　　 D. remove

30. A. wasting　　　　 B. focusing　　 　　 　C. exploiting　　　 　 D. sharing

21. 求证：函数，在区间上是减函数。

20. 已知集合，，若，求的取值范围。

19. 求下列函数的定义域

　　　 (1)　　 　　　　　　　　　　　　　 (2)

18.已知全集为，集合，集合。

　　　 求(1)　　　 (2)　　　 (3)

17．已知下列集合：

　　　 ；

　　　 ；

　　　 ；

　　　 ；

　　　 ；

　　　 (I)用列举法表示上述各集合；

　　　 (II)对集合，如果使，那么所表示的集合分别是什么？

16. 函数的值域为　　　　　　 ，函数的值域为　　　　　　　　　　　

15．不等式的解集为，则的取值范围是　　　　　　　　 。