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.

请问这道题为什么选A不选E呀

K+7= 3n+9 (3n+9 可以除以3, 为什么说 K(K+7) 可以被3整除?) 问题从条件2可以推出n可以被6整除？ 问题3n+9 如何被2整除？搞不明白，老师

这题D和E为什么应该选E呀

请问这道题A选项和D选项的区别是什么，为什么不能选A呀？

这道题为什么选B？E选项的定位句在哪里？

这道题应该怎么判断选E啊，错选了A

这道题选E是因为intact可以做副词吗，D选项为什么不能选

我是看阶段一网课 里面有开根号 就是rate 速率不变，B和速率成反比， A平方和速率成正比，B 增加了100% (2倍), 为了保持速率不变，A平方* 2 为何要开根号？

这道题答案说选D，为什么选D呀

这道题应该怎么判断哪个是main conclusion，哪个是intermediate conclusion