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.

请问数学老师 条件2为什么成立 谢谢老师

老师您好，这道阅读理解不会做，用定位的方法读了原文也没太懂为什么选D

文章的最后一句话回答了这个问题，也就是C选项，我不懂为什么正确答案是B

ken老师你好，这道题目我的思路是设97、98、99依次为a、b、c，根据题目得出b=C+y; b=a+x。条件1）x>y，可以得出a<c。 第二个条件不太懂。而且这道题目的开始的的less、 more in 1999，这些术语我转化成公式就浪费了半个小时，想问老师有没有更高效的解决办法？

请数学老师讲解下思路

麻烦老师给我讲解一下这一题，通过The body…was that of the man ，身体是那个男人的一部分，而不是身体是那个男人。这个点排除ABC. DE关于时态部分不是很清晰

请数学老师解答下第三个为什么不行

请数学老师帮我解答下，再讲下怎么画图 谢谢老师

麻烦老师给我辨析一下图1和图2，关于图1那题当时选错之后机构老师给我解答的是40 to 44 million years 是一个时间区间，不能用estimate at 因为 at 有精确到某个点的意味。那么图2的正确答案是不是因为3.47 billion years 是一个精确的年份所以要用 at 。。

麻烦老师给我解答一下这题，这题BUT后面主要想表达的核心语意是 家庭用电少于百分之一和家里面的电仍然是由蜡烛提供。我觉得B 顺着读下去也能表达这个语意，就是 我觉得AB 都能表达这个语意，关于两者的差异我不是很清晰 麻烦老师帮我辨析一下