陆旭老师，我有一些做过的assumption题目取非的句子搞不清，你能帮忙看下吗(不说这道题目的解题思路，单纯就是取非问题，特别是双重否定或者从句里面有否定词） 1.No part of a person’s brain that is damaged by a stroke ever recovers.---> some part of a person's brain that is damaged by a stroke ever recovers. 2.Impairment of linguistic capabilities does not occur in people who have not suffered any damage to any language center of the brain.这个句子我不太会取非，正过来说这个句子就是Impairment of linguistic capabilities occurs in people who have suffered any damage to any language center of the brain.那么我取非是Impairment of linguistic capabilities occurs in people who have not suffered any damage to any language center of the brain. 3.If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages at least one of them. 取非If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages nothing of them. 4.这题出现两个not The collection fee will not significantly affect the purchasing power of most residents, even if their households do not reduce the amount of trash they put out. 我取非直接去前面的not: The collection fee will significantly affect the purchasing power of most residents, even if their households do not reduce the amount of trash they put out. 5.这个也差不多 Not all steel producers were unaffected by country A’s newly imposed tariffs. 我取非All steel producers were unaffected bycountry A’s newly imposed tariffs. 6.There are no plants native to western Africa that, if domesticated, could serve as staple food crops. 这个if domesticated是不是可以不管，直接改成There are some plants native to western Africa that, if domesticated, could serve as staple food crops.

讲解

DS：已知9个数的平均数是43，求标准方差 1）最小的那个数是43 2）最大的那个数是43

一个数n的因子有2，3，5，n < 200，求n？ 条件1：4不是他的因子 条件2：9是他的因子

一辆火车走600 miles的路程，一般需要10h；火车中间走了一段速度20 miles的路；接下来是速度60miles的路，问速度60miles走了多久？ 条件1：速度20 miles走了3个小时 条件2：600 miles路程平均速度为56miles

一个数被10r整除，但不被10r+1整除，求r？ 条件1：这个数被25整除不被26整除 条件2：这个数被56整除不被57整除

数学考了一道，本来某一天下午两点水池剩n方水，每小时漏1/4方，每天下午一点会加进去14方，问水池剩m方的时候是星期几几点？

一个长方形长x宽y，能不能比较沿x边卷起的圆柱体体积和y边卷起圆柱体的体积？ 条件1：2x大于y 条件2：x小于3y

一个公司准备给一个地区中大于等于65，并且在当地呆的时间小于等于5年的人，发放谋谋福利，问这部分所占比例？ 条件1：该地区≥65岁的占比（某个值） 条件2：该地区呆的时间≤5年的人占比（某个值）

问x^y是否是odd？ 条件1：x是odd 条件2：可以求出来y是odd

编号1-8的蓝木板放到一个箱子里，编号1-8的红木板放到另一个。每个箱子各抽一块板，问抽到蓝木板和红木板编号一样的几率是多少？ 老师为什么不是 1/64?