题干：debt/population的范围是否在【495,505】内？
1.debt四舍五入到十亿分为为43,000,000,000，则42,500,000,000<=debt<=43,400,000,000 ,未知人口数量，不充分
2.人口四舍五入到百分位为86,000,000，则85,500,000<=人口<=86,400,000 ,未知debt数量，不充分
1+2 42,500,000,000/86,400,000得d/p下限，43,400,000,000/85,500,000得上限，范围大于495到505的范围，即有可能满足也可能不满足题干，不充分

· 原文最关键的assumption：“两种物质一致”，所以lab的F可用用来研究自然环境
· 类比的对象：实验室合成的F和自然形成的富勒烯
· 推翻类比：类比对象的不同点——D选项：天然存在的F以先前未知的晶体结构排列，因此与lab合成的不同
但B选项没有表明陨石撞击M的环境和实验室里不同，不能否定关键assumption

（A）前面一个their多余
（B）a group做同位语，代borrows✅
（C）such无具体含义
（D）（E）应该用过去式，非一般现在时

d) is incorrect because it misuses a "which" construction.

all constructions built on preposition + "which" - such as of which, from which, some of which, with which, etc. - must be used in the same way as "which" itself.

in this case, the "which" is trying to refer to "several posts", which is way too far away from the comma to be acceptable.

if this is really a gmat problem, then the quality of those problems is declining at an alarming rate (or the problem writers were asleep, drunk, etc. when they wrote this problem ... ugh)

sequence=数列（就是普通数列而已）
然后就是简单的 平均数*个数=总和

by前面可以加逗号吗

花了5分钟算了两遍2280……果然审题错了就会陷入思维定式啊怎么复算都没用

设本年花费x，存y

问的是没被吸收的光线！！！

不能懒，要手动算一下

6是余数，表明除数大于6

（1）所有有antilocks brakes的都有automatic transmission，但是还是不知道其中任何一个的数量

当m 0 ， mv

条件1：取8和3的和是prime number，n>80。条件2：十位数最大质数只能是7，所以n

通过增加oatmeal来增长利润，加强。A:免费咖啡可能降低购买oatmeal的欲望。B:原料便宜，不容易腐烂，这边其他早餐铺有优势，这是一个好处。 C:无关。 D:无关。 E:供应量减少，利润少。

因为科学进步要创造力，所以科学进步要艺术课程。艺术课程需要导致创造力。

书中附表没死 实际死了 结论：书写于死前
假设：当时作者用的附表是真实的

A) so gradual as to be indistinguishable
"so... as to be..." is a correct idiom.

B) so gradual so that they can be indistinguishable
"so... so that..." is not a correct idiom

C) so gradual that they are unable to be distinguished
This one is tough, because it's not grammatically or idiomatically incorrect. "So... that" is a correct idiom. It's certainly wordier than A, and there also seems to be a disconnect in meaning. If something is "indistinguishable," then people are not able to distinguish it. Here, saying that the "shifts... are unable to be distinguished," then the lack of ability is on the part of the shifts, and not on the people distinguishing. This is a case in which passive voice alters the meaning slightly, and therefore makes less sense.

D) gradual enough not to be indistinguishable
"gradual enough" means something different from "so gradual." "Enough" implies a sufficient quantity, above a certain threshold - "I have enough money to by the new laptop." "So" is a qualifier meaning "to such a degree that." For example, "I have so much money that I could buy all of the laptops in the world." It doesn't imply any threshold.

E) gradual enough so that one cannot distinguish them
Same issue as in D.

The correct answer is A.

题目要求是 performed by the government ministry 所以C不行。
是their plan to test for the fungal rot，所以B不行，只能label 无益于检测
E：没有detect出fr的company也可能有fr，没有解决问题

average (arithmetic mean) of the x-coordinates 除以3而不是除以2