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.

PS：问49.987*9.879／0.253化简结果最接近哪一个？ 选项a.b.c忘记了，d是1700，e是1800

数学书60页32题，有多少小于20的正整数等于3的正倍数与4的正倍数只和，答案说10个，我怎么查都是11个

PS：一个数是两位数，这个数大于11，个位数和十位数加起来的和是质数，问这样的 数有多少个？

57)If m is a positive odd integer between 2 and 30, then m is divisible by how many different positive prime numbers? 1)m is not divisible by 3. 2)m is not divisible by 5. 条件1 我理解的是 M 只能2到30之间，那么就有5，7，11，13，17，19，23，29，这么多个prime numbers. 条件2 我理解的是 M 可以是 3，7，9，11，13，17，19，21，23，27，29 这些，21可以被3和7除， 我判断条件1完全可以，条件2 我不太确定

62)if d is the positive integer and f is the product of the first 30 positive integers what is the value of d? (1) 10d is a factor of f. (2) d > 6 这个题目说d 是一个正整数，f 是30！阶乘，d的值多少， 这个题应该怎么推理？

DS：说一个整数N，最大不超过50，把从1到N的所有数拉出来列一起，数字里出现4的数字有几个？ 条件1：这些数里出现0的个数是出现4的个数的数字少11； 条件2：说N这个数是某个prime number的平方

错选了D，麻烦老师分析一下这题的时态！

错选了最后一个，麻烦老师讲解一下！

老师麻烦讲解这道题 Making things even more difficult has been general market inactivity lately, if not paralysis, which has provided little in the way of pricing guidance. A has been general market inactivity lately, if not paralysis, which has provided B there is general market inactivity, if not paralysis, lately it has provided C general market inactivity, if not paralysis, has lately provided D lately, general market inactivity, if not paralysis, has provided E is that lately general market inactivity, if not paralysis, which provides

讲解～