2. 用2B 铅笔把答题卡上相应题号中正确答案的字母涂黑。答案应涂写在答题卡上，否则无效。
Part I Reading Comprehension(共20题，每题2分，共40分)
Directions: There are 4 passages in this part. Each passage is followed by some questions or unfinished statements. For each of them there are 4 choices marked A, B, C and D. You should decide on the best choice and mark the corresponding letter on the Answer Sheet with a single line through the center.
Questions 1 to 5 are based on the following passage.
American researchers have developed a technique that may become an important tool in fighting AIDS. The technique stops the AIDS virus from attacking its target-cells in the body's defense system. When AIDS virus enters the blood, it searches for blood cells called T4 lymphocytes(淋巴细胞). The virus connects to the outside of T4 lymphocytes, then forces its way inside. There it directs the cells' genetic(基因的) material to produce copies of the AIDS virus. This is how AIDS spreads.
Researchers think they may be able to stop AIDS from spreading by preventing virus from connecting to T4 cells. When AIDS virus finds a T4 cell, it actually connects to a part of the cell called CD4 protein.
Researchers want to fool the virus by putting copies or clones of the CD4 protein into the blood. This way the AIDS virus will connect to the cloned protein instead of the real ones. Scientists use the genetic engineering methods to make the clones. Normally a CD4 protein remains on the T4 cell at all times. The AIDS virus must go to it.
In a new technique, however, the cloned CD4 protein is not connected to a cell. It floats freely, so many more can be put into the blood to keep the AIDS virus away from real CD4 proteins on T4 cells. One report says the AIDS virus connects to the cloned proteins just as effectively as to real protein. That report was based on tests with blood cells grown in labs. The technique is just now beginning to be tested in animals. If successful, it may be tested in humans within a year.
1. The new technique can ________.
A. cure AIDS B. kill the AIDS virus
C. prevent the AIDS virus from spreading D. produce new medicines for AIDS
2. When the AIDS virus enters the blood, it is reproduced by ________.
A. the inside of the virus itself B. any blood cells in the body
C. the CD4 protein D. the genetic material of T4 cells
3 The AIDS virus connects to cloned proteins instead of to the real ones because ________.
A. the cloned proteins stay on the T4 cells
B. the cloned proteins can float freely in the blood
C. it connects to cloned proteins more effectively than to the real ones
D. the cloned proteins are made by genetic engineering methods
4. Which of the following statements is NOT true?
A. The new technique has been tested in labs. B. The new technique is being tested in animals.
C. The new technique may be tested in humans. D. The new technique is now under clinical test.
5 Which of the following could be the best title of this passage?
A. AIDS---a Fatal Disease. B. A New Technique in fighting AIDS.
C. A Report on the Spread of AIDS Virus. D. The Technique of Cloned CD4 Protein.
Questions 6 to 10 are based on the following passage.
During the early ears of last century, wheat was seen as the very lifeblood of Western Canada. When the crops were good, the economy was good; when the crops failed, there was depression. People on city streets watched the yields and the price of wheat with almost as much feeling as if they wee growers. The marketing of wheat became an increasingly favorite topic of conversation.
War set the stage for the most dramatic events in marketing the western crop. For years, farmers mistrusted speculative(投机的)grain selling as carried on through the Winnipeg Grain Exchange. Wheat prices were generally low in the autumn, but farmers could not wait for markets to improve. It had happened too often that they sold their wheat soon after harvest when farm debts were coming due(到期)，only to see prices rising and speculators getting rich. On various occasions, producer groups asked for firmer controls, but governments had no wish to become involved, at least not until wartime wheat prices threatened to run wild.
Anxious to check(控制) inflation(通货膨胀) and rising living costs, the federal government appointed a board(董事会) of grain supervisors to handle deliveries from the crops of 1917 and 1918. Grain Exchange trading was suspended (暂停) and farmers sold at prices fixed by the board. To handle the crop of 1919, the government appointed the first Canadian Wheat Board, with full authority to buy, sell, and set prices.
6. The author uses the term “lifeblood”(Line1, para1.) to indicate that wheat was _______.
A. difficult to produce in large quantities B. was easily affected by animals and plants
C. essential to the health of the country D. expensive to gather and transport
7. According to the passage, most farmers’ debts had to be paid __________.
A. when the autumn harvest had just been completed
B. because wheat prices were high
C. as soon as the Winnipeg Grain Exchange demanded payment
D, when crop failure caused depression
8. According to the passage, wheat prices became uncontrolled because of conditions caused by _____.
A. farmers B. supervisors
C. weather D. war
9. The word “check” (Line 1, Para.3) could best be replaced by which of the following?
A. control B. investigate
C. finance D. reinforce