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。

求may老师解答

求may老师解答

老师你好，数学课本第29页例4题，我没看懂解答1和2中的组合问题。谢谢！

这一题没看懂是怎么解M和N的，为什么等于84？不是改86吗？

老师没听懂，哪里来的2呢

2的三次方 5的三次方是什么呀？

np 2*2是什么意思 不懂为什么选E

老师你好 这道题的n怎么选数字来解它 那么多数字 为什么偏要选择0 1 2…？

老师你好，左边这道题解法听明白了，但是3k加2乘以15k加3这个方程不会解，最近看好多题都是不知道怎么解方程，我全忘了。数学书我看了，有概念，但是没教怎么解方程的！请先告诉我这道题那个地方是怎么回事，再教我怎么做，谢谢！