问题 综合

读图,完成填空。(8分)

(1)当地球公转至A处时,太阳直射_____     _,地球上出现极夜的范围是____ __    _。(66.5° N --90° N、66.5° S --90° S)

(2)地球公转至B处时,太阳直射______  _,时间是______   _前后.

(3)当地球在公转轨道上由C向D转动的过程中,泰州市由_______季节向_______季节过渡,昼夜长短变化是白天越来越_______。(长、短) 

(4)在图中标出地球公转的方向。

答案

(1)北回归线  66.5° S --90° S.

(2)南回归线  9月22日或23日.

(3)冬 春 长.

(4)略.

题目分析:

(1)当地球公转至A处时,为北半球的夏至日,太阳直射北回归线,北极圈之内(66.5° S --90° S)出现极夜现象.

(2)地球公转至B处时,为北半球的秋分日,太阳直射赤道,时间为9月22日或23日.

(3)当地球在公转轨道上由C向D转动的过程中,泰州市也就是由冬至(冬季)向春分(春季)过渡,白天越来越长,黑夜越来越短.

(4)地球公转的方向是自西向东,为逆时针.

单项选择题
问答题

Exactly where we will stand in the long war against disease by the year 2050 is impossible to say. (46) But if developments in research maintain their current pace, it seems likely that a combination of improved attention to dietary and environmental factors, along with advances in gene therapy and protein targeted drugs, will have virtually eliminated most major classes of disease.

From an economic standpoint, the best news may be that these accomplishments .could be accompanied by a drop in health-care costs. (47) Costs may even fall as diseases ’are brought under control using pinpointed, short-term therapies now being developed. By 2050 there will be fewer hospitals, and surgical procedures will be largely restricted to the treatment of accidents and other forms of trauma. Spending on nonacute care, both in nursing facilities and in homes, will also fall sharply as more elderly people lead healthy lives until close to death.

One result of medicine’s success in controlling disease will be a dramatic increase in life expectancy. (48) The extent of that increase is a highly speculative matter, but it is worth noting that medical science has already helped to make the very old (currently defined as those over 85 years of age) the fastest growing segment of the population. Between 1960 and 1995, the U.S. population as a whole increased by about 45%, while the segment over 85 years of age grew by almost 300%. (49) There has been a similar explosion in the population of centenarians, with the result that survival to the age of 100 is no longer the newsworthy feat that it was only a few decades ago. U.S. Census Bureau projections already forecast dramatic increase in the number of centenarians in the next 50 years: 4 million in 2050, compared with 37, 000 in 1990.

(50) Although Census Bureau calculations project an increase in average life span of only eight years by the year 2050, some experts believe that the human life span should not begin to encounter any theoretical natural limits before 120. years. With continuing

(47) Costs may even fall as diseases ’are brought under control using pinpointed, short-term therapies now being developed.