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{{B}}A New Finding{{/B}} 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 pe A. Radiation has contributed to the disease. B. Putting a lot of people from rural area in a large towns increases the risk of childhood leukaemia. C. Population mixing is the most important reason for leukaemia cluster. D. Childhood leukaemia is caused by an unusual infection. [简答题]分析研磨体装填充量过多的后果？
[单选题]在匀强磁场中有效长度为L的直导体,以速度为V______于磁场方向运动时,在导体中将产生感应电动势。( )
A..平行 B.垂直 C.交叉 [单项选择]关于价格指数，下列说法不正确的是（）。
A. 月环比价格指数，反映某商品(或商品集团)与上月比较的价格变动 B. 同比价格指数，反映某商品(或商品集团)与上年同期(月)比较的价格变动 C. 居民消费价格指数是度量通货膨胀的一个重要指标 D. 在我国，居民消费价格指数不包括居住类产品 [单选题] 触电事故季节性明显,特别是()月,事故最为集中。
A.1.至3. B.3.至6. C.6.至9. D.9.至12. [简答题]怎样才能使学生对教育活动有实质性的参与？
[判断题]在中国古建筑中同样有门当户对的说法。
[多选题]消防员灭火防护胶靴适用于一般火场、事故现场进行灭火救援作业时穿着。但不能用于( )(中)
A.有强腐蚀性液体 B.气体存在的化学事故现场 C.有强渗透性军用毒剂 D.生物病毒存在的事故现场 E.带电的事故现场 [多选题]遇有六级以上强风、浓雾等恶劣气候,不得进行何种作业?( )
A.悬空高处作业 B.高处作业 C.露天作业 D.露天攀登 E.电工作业 [单选题]试样是按规定从试板上切取( )供试验用。
A.A、焊缝金属 B.B、熔合区金属 C.C、热影响区金属 D.D、样品 [多项选择]下列属于宫廷画代表作的有（）。
A. 张择端的《清明上河图》 B. 马远的《雪图》 C. 夏圭的《长江万里图》 D. 董浩的《御制诗意图》 E. 苏汉臣的《货郎图》 [单项选择]
As the plane circled over the airport, everyone sensed that something was wrong. The plane was moving unsteadily through the air, and (31) the passengers had fastened their seat belts, they were suddenly thrown forward. At that moment, the air-hostess (32) She looked very pale, but was quite (33) Speaking quickly but almost in a whisper, she (34) everyone that the pilot had fainted and asked if any of the passengers knew anything about machines or at least how to drive a car. After a moment’s (35) , a man got up and followed the hostess into the pilot’s cabin. [单项选择]
In low - speed network ,it is usually adequate to wait for congestion to occur and then react to it by telling the source of packets to slow down. In high - speed networks, this approach often works poorly, because in the （1） between sending the notification and notification arriving at the source, thousands of additional （2） may arrive. In ATM network , a major tool for preventing （3） is （4） control. When a host wants a new virtual （5） ,it must describe the traffic to be offered and the service expected. （3）处应选择（）A. collision B. congestion C. drop D. delay [判断题]为制止违法犯罪行为，人民警察可以采取强制手段；根据需要可以依法使用警械；使用警械不能制止的，可以依法使用武器。
A.正确 B.错误 [判断题]税务稽查的任务是税务稽查职能的具体化，包括手段与目的两个层次的内容，其中，查处税收违法行为是手段。（ ）
A.正确 B.错误 [单选题]无缝线路轨枕应均匀布置,轨枕配置 1667 根/km 的线路轨枕间距应为 600mm,轨枕配置 1840 根/km的线路轨枕间距应为( )。
A.362mm B.486.6mm C.518.8mm D.543.5mm 我来回答: 提交
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