| Any physical theory is always
provisional, in the sense that it is only a hypothesis: you can never prove in.
No matter how many times the results of experiments agree with some theory, you
can never be sure that the next time the result will not contradict the theory.
On the other hand, you can disprove a theory by finding even a single
observation that disagrees with the predictions of the theory. As philosopher of
science Karl Popper has emphasized, a good theory is characterized by the fact
that it makes a number of predictions that could in principle be disproved or
falsified by observation. Each time new experiments are observed to agree with
the predictions the theory survives, and our confidence in it is increased; but
if ever a new observation is found to disagree, we have to abandon or modify the
theory. At least that is what A. a new hypothesis about gravity B. careful measurements of Mercury’s motion C. new practical considerations of Newton’s theory D. newly predicted observations [单项选择]小王在电子商务网站订了东西因为某些原因一直没有付款一般将订单保存（）天后自动删除。
A. 5天 B. 6天 C. 7天 D. 8天 [单选题]接触网作业车过轨检查技术标准之一是车轮踏面擦伤深度及局部凹下深度( )。
A.≤1mm B.≥1mm C.<1mm D.>1mm [单选题]使用小型钢轨打磨机打磨钢轨肥边后，进行检测验收的量具是（ ）。（应知应会-《铁路线路修理规则》-第4.12.4条）
A.木折尺 B.钢卷尺 C.1m直尺 D.塞尺 [判断题]分支接头用于将三根及以上电缆相互连接的接头。
A.正确 B.错误 [单选题]化肥生产用电按需量计收电基本电价是（ ）元/千伏安。
A.21 B.28 C.30 D.34 [单选题]对于采场内巷道有裂隙或局部的不能使用崩炮处理的浮石,可以采用()的方法处理。
A.派人监护 B.悬挂标志 C.顶木立柱 [单选题]所属各站段指挥中心（生产调度）防洪值班人员应()小时值守，实时做好降雨预报预警信息的接收、转达和应急响应情况的反馈。
A.8 B.12 C.16 D.24 [判断题]独头巷道发生火灾时，要维持局部通风机原状，不得随意开启或停止局部通风。
A.正确 B.错误 我来回答: 提交
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