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问题 单项选择题

政府通过增加财政支出或减税等措施扩大社会需求，以刺激经济增长，实现充分就业的政策为( )的财政政策。

A．开放性

B．扩张性

C．中性

D．紧缩性

答案

参考答案：B

解析： 扩张性财政政策，是指通过财政收支活动来增加和刺激社会总需求的政策。在社会总需求不足的情况下，政府通常采取扩张性的财政政策，通过减税、增加财政支出等手段扩大社会需求，进而提高社会总需求水平，缩小社会总需求与社会总供给之间的差距，最终实现社会总供需的平衡。

单项选择题

生态功能指数包括功能、结构和（）三个方面。

A、清洁力

B、协调度

C、恢复力

D、活力
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单项选择题

British cancer’ researchers have found that childhood leukaemia is caused by an infection and clusters of cases around industrial sites are the result of population mixing that increases exposure. The research published in the British Journal of Cancer backs up a 1988 theory that some as yet unidentified infection caused leukaemia--not the environmental factors widely blamed for the disease.

"Childhood leukaemia appears to be an unusual result of a common infection," said Sir Richard Doll, an internationally-known cancer expert who first linked tobacco with lung cancer in 1950. "A virus is the most likely explanation. You would get an increased risk of it if you Suddenly put a lot of people from large towns in a rural area, where you might have people who had not been exposed to the infection. " Doll was commenting on the new findings by researchers at Newcastle University, which focused on a cluster of leukaemia cases around the Sellafield nuclear reprocessing plant in Cumbria in northern England. Scientists have been trying to establish why there was more leukaemia in children around the Sellafield area, but have failed to establish a link with radiation or pollution. The Newcastle University research by Heather Dickinson and Louise Parker showed the cluster of cases could have been predicted because of the amount of population mixing going on in the area, as large numbers of construction workers and nuclear staff moved into a rural setting. "Our study shows that population mixing can account for the (Sellafield) leukaemia cluster and that all children, whether their parents are incomers or locals, are at a higher risk if they are born in an area of high population mixing," Dickinson said in a statement issued by the Cancer Research Campaign, which publishes the British Journal of Cancer.

Their paper adds crucial weight to the 1988 theory put forward by Leo Kinlen, a cancer epidemiologist at Oxford University, who said that exposure to a common unidentified infection through population mixing resulted in the disease.

Who first hinted at the possible cause of childhood leukaemia by infection（）

A. Leo Kinlen

B. Richard Doll

C. Louise Parker

D. Heather Dickinson
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