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.

数学：请问老师这道排列组合怎么解 感觉好复杂

老师，请问这道题思路是什么？

老师，求该题解题思路

DS：说一个女生有一些 tax deductible 其中捐给 b 让她少交了 210 的税，问什么忘记 了求补充，好像是她总收入是多少？ 条件 1：给了税率是 28% 条件 2：给了可税工资（income-deductible）是个五位数。 income*0.28-（income-deductible）*0.28=210 构筑纠结很久 因为题里面说捐给 b 只是 deductible 其中一项，还有其他未知，所以最 后选了 e，现在感觉选 c 请问陆老师，应该选什么？谢谢！

DS：n 是三个不同质数的积，这些质数都在 1-15 之间，问 n 是否＜700？ 其中一个条件是 n 与 70 没有公约数 【补充】 DS：x,y,z 是三个质数，xyz<700？ 条件 1：三个数不大于 14 条件 2：三个数里面有 70 的因数 s 轩辕十四 12/20 【122-补充】 DS：三个整数，问他们的积和一个常数的关系 条件 1：都是小于 15 的质数 条件 2：是 30 的 factor 构筑：这个好像也是个变体吧，好迷啊 ggggggbbbbbb bb 12/20 【122-补充】 DS：Integer p: is p>700? 条件 1：p is product of three prime numbers from 1-15 条件 2：p has no common factor with 70 请问陆老师，这道题选什么？谢谢！

DS：2x^2+bx+8=0，只有一个实数根，求那个字母的值？ 条件 1：b<0 条件 2：lxl>5 x的绝对值 请问陆老师，这道题选什么？谢谢

想请教一下陆老师，我觉得这道题应该是用相似三角形做，看了图觉得应该是用角1和角2相等来证明。但是由题干给的条件，我不知道如何得出角1和角2相等

请问老师图里的这道语法比较，不太明白，如何区分到底比较的是什么呢？谢谢

请问May, 我这道题不知道怎样做？谢谢！

请问May老师，请问这题选5 吗？