Prospecting for gold during the California gold rush was a relatively easy task, 【since 】erosion*, prehistoric glacier movement*, and ancient, gold-bearing riverbeds* （thrust to the surface by volcanic activity）【put 】gold literally 【within reach of】 anybody with a pan or shovel.
在加利福尼亚淘金热期间寻找黄金是一件相对容易的事情，【因为】侵蚀、史前冰川运动、（被火山运动推到地表来的）古老的产金河床，使任何人用平底锅或铲子都可以【接触到】黄金。

reach for sth.：伸手抓某物；
reach of sb.：在某人能触及到的范围内--【within reach of】 anybody

erosion 抽, prehistoric glacier movement 抽 , & ancient, gold-bearing riverbeds实
三者并列没有问题，因为都可以发出put这一动作，虽然前两个是抽象性名词，后者是具体的实物名词，但功能相同，可以并列。

thrust在此为过去分词，修饰 reiverbed

D选项：rate的of型所有格中（做rate的定语）的核心词是fatty foods（consumed in France and the United States是过去分词短语）。在逻辑上，具有相同比率的应该是两个国家人消耗食物这件事情，而不是食物本身拥有比率（食物自己没法有比率）。另外，通常，the rate of food指代的是“食物的价格”。本选项在语意上显然不是“食物的价格在美国法国相同”。

E选项：同(D)里，本选项中of型所有格中的核心词是people（consuming fatty foods是现在分词短语）。逻辑上具有相同比率的也不能是人本身。

four times as likely as和four times more likely than都是可以的，且含义相同。

the number of+复数名词，谓语动词用单数；a number of +复数名词，谓语动词用复数。

the REAL issue, though, is "unqualifying" -- this is incorrect. "unqualifying" means "not meeting some sort of standard for qualification".
the intended meaning here is "unqualified", which means "without any sort of restriction or reservation". 无条件的

Ron： i'm loath to use apostrophe + "s" for anything but humans, animals, and the like. ‘s’更偏向一个人

(a)
"so that" is wordy, but also doesn't make literal sense here -- "X so that Y" implies that X is an action taken toward the goal Y. i.e., i studied hard so that i could get a good grade.
needing time is not an action taken toward a goal, so this doesn't make sense.

(b)
read literally, this sentence doesn't give any indication that the workers themselves need the time -- it just states that the time is "needed" (we don't know by whom) when the workers are working.

(c)
present tense doesn't make sense

(d)
correct

(e)
present tense doesn't make sense

who只能指代人，whose既可以指代人也可以指代物。

with a thesis that is a simple one：介词短语作为状语，修饰前面的动作v.-- publish （语义不通）
whose thesis was simple: consumers have：定语从句修饰前面的名词n. --Shopping for a Better World. （语义合理）

In 1988, the Council on Economic Priorities began publishing 【Shopping for a Better World, whose thesis】 was simple: consumers have the power to change companies by the simple expedient of refusing to buy.
1988 年，经济优先委员会开始出版《为更美好的世界而购物》，《为更美好的世界而购物》的论点很简单：消费者有权通过拒绝购买的简单权宜之计改变公司。

such：
作代词，指代前面提过的东西或事情，如：
She longed to find somebody who understood her problems, and in him she thought she had found such a person. 她渴望找一个理解她困难的人，她觉得他就是这样一个人。
Accountants were boring. Such was her opinion before meeting Ian! 做会计的个个乏味。在认识伊恩以前她一直这样想。

诸如此类的，如：
We like such fruits as apples and bananas.

起强调作用，如：
It's such a beautiful day!
This issue was of such importance that we could not afford to ignore it.

Comma+participle" can modify the subject of the previous main clause. This sort of modifier should actually satisfy TWO requirements:
1) it should apply most nearly to the subject of the preceding clause (as you've said); and, even more importantly,
2) it should have one of the following RELATIONSHIPS to that clause:
* immediate consequence
* simultaneous, but lower-priority, action
here, this modifier doesn't have either of these 2 relationships to the main clause, so it's used inappropriately.

when we say "immediate consequence, we mean a consequence that is proximate, immediate, and produced as an essentially unavoidable result of the main action. for instance:
the bullet entered Smith's brain, killing him instantly --> this is an immediate and automatic consequence; if the bullet does this, then smith will be killed.

John scored 90 on the most recent test, raising his overall average by two points --> again, an immediate and automatic consequence; if john gets this score, there will automatically be the stated consequence for his average.

in the problem at hand, drawing new conclusions is not an automatic and essentially unavoidable consequence of amassing the knowledge in question; the researchers must actively go beyond just amassing the knowledge to draw those conclusions.

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)

set原型助动词do 所以应该did 或have done AB错误
C to be 和haven been对应

sth be among sth,位于……中，是……之一，如：
He's among friends now. 他现在被朋友们环绕着。
A British woman was among the survivors. 幸存者中有一位英国妇女
He was among the last to leave. 他是最后离开者之一。
She was among the best writers in American during 20th .她是20世纪美国最棒的作家之一。

本题，the thread and the decline are among the challenges.表示“威胁和下降是挑战之二”。
A，the declining sales核心词是sales，挑战包括对手的威胁以及收入，错误，是收入的下降
D，倒装形式的独立主格结构，实际上是the threat of a rival’s multibillion-dollar patent-infringement suit and the decline in sales of the company’s powerful microprocessor chip among them,倒装可以避免头重脚轻，更重要的是among them中的them离其指代对象challenges更近。

两个并列分句中，当谓语动词为系动词或者become时，后面一句一定要省略。并且and一并省略。
还原倒装：Frances Perkins' investigations of the garment industry were so dogged, her lobbying for wage
and hour reform (was) so persistent, that Alfred E. Smith and Franklin D. Roosevelt recruited Perkins to
work within the government, rather than as a social worker.

1) intend的固定搭配： intend的动作发出者必须是生物。
intend somebody/something to do sth.
intend to do/doing sth. （后面跟to do和ing都可以）
intend that
be intended to do sth.：被用来做某事
be intended for somebody/something：表示书、电影、药品等专为…而设计或制造。
(2) intent的固定搭配：
noun. with intent (to do sth) 注意intent前没有the
intent of doing
adj. be intent on/upon (doing) sth： to be determined to do something or achieve something
intent on/upon 专注于
Intent upon her work, she didn't notice the cold.

Intend to do 的固定搭配，发出者必须是人
所以rule is intended to
"rules intending..." is incorrect, since the rules aren't intending to do anything. rules don't have intentions, although their authors do.
this is a passive type construction. the rules are intended to do x, y, and z, so you need "intended", not "intending".

2. namely的用法十分灵活：（=that is to say, along with） . 它是副词，后面不能直接加句子
（1）补充说明前面离它最近的名词成分； e.g.: The other change, namely the increase in electronic equipment, has slowed down.
（2）补充说明句子主语； e.g.： One group of people seems to be forgotten, namely pensioners.
（3） namely后面跟从句解释前面的名词成分； e.g.: On the next trip, I solved part of the problem, but after discussing the situation with AB on the phone an alternative solution was at hand; namely, that from 1987 onwards I would spend my winters playing for Queensland.

选项C.in order to do表示为了...，导致后半句没有主语；to do比in order to简洁

A. * "so many ... such that" is an incorrect idiom.
the correct idiom is "so ADJ ... that", and is used to emphasize the unusual extent of ADJ. (in this case, ADJ is "many".)

B. * you need commas around the appositive modifier ("once 75 percent of the population").
* "are now accounting for" is bulky and unnecessary (especially vs. "account for" in the other choices).

C. * most obvious problem: you can't use "which" for people.
* the "that" at the beginning is ungrammatical.

* "such that" doesn't make sense.
in fact, i don't think you should pick a sentence with "such that" in one piece. I would be suspicious of any sentence that has "such that" IN ONE PIECE.
"such NOUN that" is a perfectly respectable construction in formal English though.
the ONLY non-awkward, correct sentences i've seen with "such that" are sentences about math or physics (e.g., "choose x and y such that x + y = 10").

D. * same problem with "such that".
* "only" is misplaced. the purpose is to show that 1/2 is a smaller fraction than before, so "only" should be placed directly before "half".

E. correct.
* it's idiomatic "so many ... that"
* and everything else is ok, too.

you can only say "X results in Y" when X is an ACTION. if X is an OBJECT, you can NEVER say that X "results" in anything.

A. 将small cars的now和at any time相比较，现在的小车和其他时候的该小车做比较，但应该将today's small cars和small cars at any other time做比较的。at any time并没有剔除掉Today的时间点。today和now重复
B. they指代的就是前面的small cars，还是将现在的该小车和其他时候的该小车做比较。at any time没有剔除掉today的时间点。they是同物指代，指代的就是前面出现的东西
C. right，those是同类指代，指代的是同类的small cars。
D. more fuel-efficient small cars有歧义，到底是更多的省油车还是更省油的车？their可能指代manufacturers也可能指代small cars
E. more fuel-efficient small cars有歧义，到底是更多的省油车还是更省油的车？at any time没有剔除today的时间点

1. ABC的in addition to and besides 都是介词用法，后面接名词或者名词成分，例如动名词和从句。最大的错误是两个用语后面的名词成分都必须在句子中与一个成份形成实际意义上的语义逻辑上的平行关系。而ABC里的possibility在后面句子中找不到对应的词。
2. ABC的It指代问题，应该是leaves，复数
3. D and E, D的possible ＋动名词 preventing and inhibiting没有E的possibly preventing or inhibiting好，原因有二，一是 D中and不如E中or在语义逻辑上更准确。Ron说这两个词是mutually exclusive，不可能用and同时发生，肯定是or。同理还有一个句子里有damage and destroy，也是应该用OR，而不能用and；二是 D中possible修饰preventing 以及inhibiting，应该用副词形式修饰这两个动作。若用形容词的possible，就用prevention更合适。