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问题 单项选择题

未经旅游者同意，旅行社不得在旅游合同约定之外提供其他有偿服务。若有违反，由旅游行政管理部门责令改正，处（）罚款。

A.1万以上3万以下

B.5000以上3万以下

C.1万以上5万以下

D.1万以上5万以下

答案

参考答案：C

单项选择题 A1/A2型题

外科最多见的真菌感染病原菌是（）。

A.粗球孢子菌

B.念珠菌

C.放线菌

D.隐球菌

E.曲菌
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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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