未知题型 水温28℃，牛蛙头低垂、不动、不吃食、便血；头部、嘴周围、背、腹、腿和脚趾等处可见粉红色溃疡，由病灶处分离到格兰阴性细菌。该病最可能的病原是（）

单项选择题 U.S. Blacks Hard-hit by Cancer Death rates for cancer are falling for all Americans, but black Americans are still more likely to die of cancer than whites, the American Cancer Society said Monday.In a special report on cancer and blacks, the organization said blacks are usually diagnosed with cancer later than whites, and they are more likely to die of the disease.This could be because of unequal (不平等的) access to medical care, because blacks are more likely to have other diseases as well, and perhaps because of differences in the biology (生物学) of the cancer itself, the report added.'In general, black Americans have less hope of surviving five years after diagnosis than whites for all cancer sites and all stages of diagnosis,' the report said.'In describing cancer statistics for black Americans, this report recogizes that many of the differences associated with race may be caused by unfair social and economic differences and unequal access to medical care.'The cancer society said blacks should be encouraged to get check-ups (体格检查)earlier, when cancer is more treatable, and it said more research is needed to see if biological differences play a role.'The new statistics emphasize the continuing importance of wiping out these unfair social differences through public policy and education efforts,'the organization said in a statement.But it also noted a drop in cancer death rates.'Cancer death rates in both sexes for all sites combined have dropped greatly among black Americans since 1992, as have incidence rates (发生率),' said the report. 第 31 题 Black Americans are more likely to die of cancer thanA．people in other countries.B．white Americans.C．all other Americans.D．their ancestors.

单项选择题 Migrant (移民的) Workers In the past twenty years, there has been an increasing tendency for workers to move from one country to another. While some countries have restricted (限制) most____________.(51) to local people, others have attracted and welcomed migrant workers.This is partiicularly the case in the Middle East,____________(52) increased oil incomes have enabled many countries to call in outsiders to improve local facilities (设施). Thus the Middle East has attracted oil-workers(53) the U.S.A． and Europe. It has also brought in workers from many other countries,____________(54) South Korea and Japan.In view of the difficult living and working____________(55) in the Middle East, it is not surprising that the pay is high to attract suitable workers. Many engineers and technicians can____________(56) at least twice as much money in the Middle East as they can in their own country, and this is a major____________ (57).Sometimes a disadvantage has a compensating (补偿的) advantage. For example,the____________.(56) living conditions often lead to increased friendship when workers have to____________.(59) on each other for safety and comfort. In a similar way, many migrant workers can save large sums of money partly because of the____________.(60) of entertainment (娱乐) facilities. The work is often complex and full of problems but this merely presents greater challenge to engineers who prefer to find solutions to problems rather than de____________(61) work in their home country.One major problem which____________.(62) migrant workers in the Middle East is that their jobs are temporary ones. They are nearly always on____________.(63), so it is not easy for them to plan ahead with great confidence. This is to be____________(64)since no country welcomes a large number of foreign workers as permanent residents.In any____________(65), migrant workers accept this disadvantage, along with others,because of the considerable financial benefits which they receive. 第 51 题A．actsB．jobsC．activitiesD．uses