| Many Americans harbor a grossly
distorted and exaggerated view of most of the risks surrounding food. Fergus
Clydesdale, head of the department of food science and nutrition at the
University of Massachusetts-Amherst, says bluntly that if the dangers from
bacterially contaminated chicken were as great as some people believe, "the
streets would be littered with people lying here and there." Though the public increasingly demands no-risk food, there is no such thing. Bruce Ames, chairman of the biochemistry department at the University of California, Berkeley, points out that up to 10% of a plant’s weight is made up of natural pesticide (杀虫剂). Says he. "Since plants do not have jaws or teeth to protect themselves, they employ chemical warfare." And many naturally produced chemicals, though occurring in tiny amounts, prove in labor A. many vegetables contain deadly natural chemicals B. almost all foods have additives C. no food is free from pollution in the environment D. pesticides are widely used in agriculture [判断题]( )39. 拆井口前，要检查油套压是否与工程设计提供的数据相符。
A.正确 B.错误 [单选题]在MPEG中为了提高数据压缩比，采用了哪些方法( )
A.运动补偿与运行估计 B.减少时域冗余与空间冗余 C.帧内图象数据与帧间图象数据压缩 D.向前预测与向后预测 [单选题]调车计划变更（）时必须停车传达。
A.辆数 B.位置 C.作业方法 D.股道 [判断题]闪燃是在一定温度下，易燃、可燃液体表面产生的蒸气，当与空气混合后一遇着火源就会产生一闪即灭的燃烧现象。( )(中)
A.正确 B.错误 [判断题]应根据不同的使用场合选择合适的液压泵，在负载大、功率大的场合往往选择齿轮泵。
A.正确 B.错误 [不定项选择题]A.新加香薷饮
A.荆防败毒散 B.麻杏甘石汤 C.三拗汤 D.银翘散 E.治疗风寒感冒应首选 [判断题]使用稳定器满眼钻具时，通常将减震器安装在近钻头稳定器之下。
A.正确 B.错误 我来回答: 提交
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