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问题 探究题

为了研究物质的某种特性，小明测出了两组两种物质的质量和体积，如下表所示。

（1）将上表空格填写完整；

（2）比较第1、2两次实验数据，可得出结论：__________________________________________；

（3）比较第1、3次实验数据，可得出论：______________________________________________；

（4）比较第1、4实验数据，可得出实验结论：__________________________________________。

答案

（1）8.9；

（2）铜的质量与体积的比值是相等的（质量与体积成正比）；

（3）质量相同的铜块与松木，松木比铜块体积大；

（4）体积相同的铜块与松木，铜块比松木质量大。

单项选择题

火把节晚上，岳父不能接女婿来家过节，是（）民族的民俗。

A.傣族

B.苗族

C.白族

D.壮族
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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.

This passage is mainly about（）

A. the cluster of leukaemia cases around the Sellafield nuclear reprocessing part

B. the kind of infection that causes childhood leukaemia

C. the causes of childhood leukaemia

D. a new finding by British scientists
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