In the country of Veltria, the past two years' broad economic recession has included a business downturn in the clothing trade, where sales are down by about 7 percent as compared to two years ago. Clothing wholesalers have found, however, that the proportion of credit extended to retailers that was paid off on time fell sharply in the first year of the recession but returned to its prerecession level in the second year. Which of the following, if true, most helps to explain the change between the first and the second year of the recession in the proportion of credit not paid off on time? (A) The total amount of credit extended to retailers by clothing wholesalers increased between the first year of the recession and the second year. (B) Between the first and second years of the recession, clothing retailers in Veltria saw many of their costs, rent and utilities in particular, increase. (C) Of the considerable number of clothing retailers in Veltria who were having financial difficulties before the start of the recession, virtually all were forced to go out of business during its first year. (D) Clothing retailers in Veltria attempted to stimulate sales in the second year of the recession by discounting merchandise. (E) Relatively recession-proof segments of the clothing trade, such as work clothes, did not suffer any decrease in sales during the first year of the recession. 这道题错选了A。 思路如下： 题目问的是为什么在经济不好，衣服卖不动的情况下，第一年零售商还不上钱第二年就能还上了。讲的是零售商还钱的问题。 当时留下的是A,C,D 排除D是因为觉得，即使刺激销售量衣服打折也不能说明能还上钱。可能打折卖1块，纵使家当全卖了也不够。 排除C是因为觉得， 那些本身经济状况就很差的在第一年被淘汰掉以后，剩下的那些没说经济状况如何啊，如果也不咋地，第二年还是得淘汰啊。 A选项当时觉得，即使credit extended，对pay off on time也无太大用处，但最起码跟原文意思接近。所以选了A。

这个是怎么算的，我只能看出要求的人数是总人数的百分之三

这题除了试数还有什么好方法吗？如果试数的话，如何快速找到适合的数呢？

条件二说的是每一项Sn都大于5吗？，但是n/（n+1）不是小于1吗？我不知道该怎么理解和使用该条件

条件2是要把对角线为8时的情况算出来吗？如果不是，应该怎么判断吗？另外五边形的面积应该怎么算呢？

这题怎么思考？还有绝对值不等式的考点有哪些啊

B单独不能成立吗？k=7带入不等式中，不是可以限制m和n的范围吗

题干不是已经能排出+和➗好了吗？因为此时式子没有意义。那两个条件为什么不能单独成立呢？这题的逻辑是什么

条件2为什么单独不成立？B做了超过50%，说明B比A效率高，那么3小时内可以完成

已知由一个符号@表示的加减乘除中的一一个符号。如果a@ (-a) =0,那么a=0.问:以下条件能否判断符号@是加减乘除中的哪一个?条件1).其中a@(a@a)=0, a=0;条件2).其中a@(b@c)=(a@b)@c. 答案：E

老师这道题和后面你讲的6和4的例子没看懂！