(46) For centuries the smoking of tobacco in cigarettes, cigars, and pipes has produced controversy over possible health hazards, but only since the 1950’s has sufficient scientific evidence accumulated to make possible a thorough evaluation of the health risk.
Scientific investigation of the relationship of smoking and health gained impetus after the beginning of the 20th century, then an increase in lung cancer was noted. As the use of tobacco increased, studies improved. (47) Although some gaps in knowledge still exist, the information now available is sufficient to permit making sound judgments, based on the converging lines of evidence.
(48) Investigators have directed their principal consideration to cigarette smoking because the health consequences attributed to it far exceed those due to smoking cigars and pipes. The widespread popularity of cigarettes is comparatively recent in man’s use of tobacco. The smoking
| Genetically modified (GM) foodstuffs
are here to stay. That’s not to say that food produced by conventional
agriculture will disappear, (61) simply that foodbuying
patterns will polarize. It may even be that GM food will become the food of
(62) because consumers come to appreciate the health benefits of
reduced pesticide use. The reason GM food will not go away is that we need a three-fold increase in food production by the year 2050 to keep (63) with the world’s (64) population growth to ten or eleven billion. It’s not just a question of more mouths to feed either. (65) is often forgotten is that all these extra people will take up space,reducing the overall land (66) for agriculture. It may well be that in the long term it is the developing world (67) benefits most from GM foods. It’s true A. and B. or C. but D. rather than [单项选择]设某系统由P1和P2两个子系统组成，当且仅当两个子系统都能正常工作时，该系统才能正常工作。若P1和P2的可靠性均为0.9，则该系统的可靠性是______。
A. 0.1 B. 0.45 C. 0.81 D. 0.9 [单项选择]
A. mass B. dwellers C. folk D. mob [多选题]消费指标包括()。
A.社会消费品零售总额 B.城乡居民储蓄存款余额 C.居民可支配收入 D.货币供应量 [单项选择]在进行数据分组时，首先考虑的是（）。
A. 分成多少组 B. 选择什么标志分组 C. 各组差异大小 D. 分组后计算方便 [单选题]220kV设备验电时，人体应与验电设备保持（）m安全距离。
A.3 B.2.8 C.2.7 D.2.55 [填空题]Ⅱ型和Ⅲ型混凝土枕中部道床应( )，并不高于轨枕顶面。
[单选题]由职位的任职者本人按照时间顺序记录工作过程,然后经过归纳提炼取得所需要资料的方法是( )
A.观察法 B.关键事件技术 C.工作日志法 D.工作实践法 [单项选择]红外激光胶片的吸收光谱峰值为（）.
A. 250nm B. 550nm C. 633nm D. 820nm E. 950nm [多选题]现场培训分为( )为目的的现场培训。
A.员工适应新岗位 B.培养人才 C. 改善绩效 D.以上都不是 [单选题]对于瞒报、谎报、迟报安全信息的行为，经调查情况属实未构成铁路交通事故，但对集团公司造成不良影响的，比照铁路交通一般（ ）类事故进行考核，追究责任单位主要领导责任。
A.A B.B C.C D.D [判断题]皮革或缝制的工作手套也可以在处理危化品时使用。
A.正确 B.错误 我来回答: 提交
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