判定系数R2的取值范围是（）。A．R2≤-1 B．R2≥1 C．0≤R2≤1 D．－

二项方程x⁴-81=0的实数解是______．

20世纪70年代将采购计划、生产能力计划、车间作业计划等纳入MRP形成（）。

A.初期MRP

B.闭环MRP

C.开环MRP

D.基本MRP

患者李某，男，7岁，因上呼吸道感染收住某医院儿科病房。当时高热39℃，咳嗽，经抗生素滴注后体温下降，第4天体温已正常，咳嗽减轻，情况好转。该医院因在搞一项关于儿童电生理无伤性检查方面的研究课题，故经患儿同意后，把患儿作为受试者。次日父母探视时发现孩子的头顶部皮肤有了个直径2mm的圆形丘疹红斑，当了解情况后，即与医生发生了争执。

对未成年人能否做人体实验，下列说法正确的是（）

A.在道德上对未成年人不能做人体实验

B.对未成年人没有伤害的人体实验可以做

C.只要未成年人同意就可做人体实验

D.只要监护人同意就能做人体实验

E.以上都不完整

明清时期中央机关总收文机构是（）。

"We’re using the wrong word," says Sean Drysdale, a desperate doctor from a rural hospital at Hlabisa in northern KwaZulu-Natal. "This isn’t an epidemic, it’s a disaster. " A recent UNIEF report, which states that almost one-third of Swaziland’s 900,000 people are infected with HIV, the virus that causes AIDS, supports this diagnosis. HIV is spreading faster in southern Africa than anywhere else in the world.

But is anyone paying attention Despite the fact that most of the world’s 33.5 million HIV/AIDS cases are in sub-Saharan Africa—with an additional 4 million infected each year—the priorities at last week’s Organization of African Unity summit were conflict resolution and economies development. Yet the epidemic could have a greater effect on economic development—or, rather, the lack of it—than many politicians suspect.

While business leaders are more concerned about the 2K millennium bug than the long-term effect of AIDS, statistics show that the workfare in South Africa, for instance, is likely to be 20% HIV positive by next year. Medical officials and researchers warn that not a single country in the region has a cohesive government strategy to tackle the crisis.

The way managers address AIDS in the workplace will determine whether their companies survive the first decade of the 21st century, says Deane Moore, an actuary for South Africa’s Metropolitan Life Insurance Company. Moore estimates that in South Africa there will be 580,000 new AIDS cases a year and a life expectancy of just 38 by 2010. "We’ll be back to the Middle Ages," says Drysdale, whose hospital is in one of the areas in South Africa with the highest rates of HIV infection. "The graph is heading toward the vertical. And yet people are still not taking it seriously. "

Most southern African countries are simply too poor to supply more than basic health services, let alone medicines, to confront the crisis. Patients in some government hospitals in Harare have to supply their own bedding, food, drugs and, in some cases, even their own nurses. Zimbabwe’s frail domestic economy depends to a large extent on informal enterprises and small businesses, many of which are going bankrupt as AIDS takes its toll on owners and employees. "The ripple effect is devastating," says Harare AIDS researcher Rene Loewenson.

More ominous are the implications for South Africa with a sophisticated industrial infrastructure as well as a widespread informal sector. While the South African government is active in promoting AIDS education, it hasn’t the money, manpower or material to cope with the attack of AIDS.

Which is the major reason for the AIDS situation in South Africa（）

A. The poor economic power in the African countries

B. The industrial infrastructure is complex

C. The informal sector is widespread

D. The lack of government concern