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。

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？