(C) "they" would have to refer to "soaring television costs", by elimination: there aren't any other plural nouns.

literally, this makes no sense, since television costs weren't "soaring" in OTHER elections.
(note that you MUST take the pronoun to stand for "soaring television costs"; you are NOT allowed to extract just "television costs" and pretend that the pronoun stands only for that.)

"have been" is an even bigger problem, though, since it implies the presence of "accounting". you can't do this unless the word "accounting" is actually present elsewhere in the sentence; it isn't.

actually, for those choices to make sense, "it" would have to be "proportion". (the proportion was greater in '92 than it was in any previous election.)

if "it/they" = "the cost(s)", then it's nonsense to use "was/were". you'd have to have "represented", "accounted for", "amounted to", etc.
'they have' or 'they did' can't make this option acceptable because "have"/"did" can't stand for "accounted for".

RON:
"essential vs. nonessential modifier".
NOTE: i've never seen this issue directly tested, so it's not important for you to be able to distinguish between the two -- the only thing that's important is for you to realize that both are ok, under certain circumstances

an "essential" modifier (which is NOT set off by commas) is a modifier that actually narrows or specifies the noun/action to which it's attached.
for instance:
our top student whose score fell below 50 received a consolation prize.
--> this doesn't refer to the top student among all of our students; this only refers to the top student among those whose scores fell below 50 points. therefore, we need the essential modifier (no commas) to narrow "our students" to "students whose score fell below 50".

a "nonessential" modifier (which IS set off by commas) is a modifier that does not narrow or specify the nouns/action to any greater degree than does the rest of the sentence; it merely provides more information about that noun/action.
for instance:
our top student, whose score fell below 50, received a consolation prize.
--> here, we are actually talking about our top student. the meaning of the sentence is that all of our students' scores were below 50, but at least our top student received a consolation prize.

(D) Importantly, in this sort of structure (NOUN1 + prep + NOUN2 + THAT..., or NOUN1 + (modifier ending with NOUN2) + THAT...), the "that"-modifier can actually modify either NOUN1 or NOUN2.
for instance:
the library has a new method of sorting cd's that makes certain genres of music easier to find. --> here, "that makes..." refers to the method of sorting.
the library has a new method of sorting cd's that don't fit into any of the traditional musical genres. --> here, "that don't fit..." refers to the cd's, not the method.
both sentences are correct.

however, in the example above, either of these two interpretations leads to an absurd sentence -- neither the method (= NOUN1) nor the mineral (= NOUN2) "was as early as the 18th century" -- so this option is flat-out incorrect.

(E) inappropriate tense.
if the past perfect is used to describe a state or description of something (as opposed to an action verb), it should generally be used to describe a state/description that is no longer the case. since leaching is presumably still an extraction method (this is not the sort of thing that is subject to change), the past perfect is inappropriate.

also, the modifier (starting with "well established") shouldn't be a nonessential modifier, i.e., it shouldn't be set off by commas.

"until healing" would apply to the subject "swelling and stiffness". those don't heal; the injured area does. therefore, you need a construction that changes the subject to "the injured area" -- or a pronoun that stands for those words, as in the actual correct answer.

题目翻译：三十天账单的平均数 等于 每天余额的算术平均。比如说条件1，20天是余额600，10天余额400，所以平均就是（20×600＋10×300)/30

反向思考更为简单。一减去完全听不到他喜欢的歌，1减去0.7的三次方。画一个数轴图更为清楚

Recovering uranium from seawater may be worthwhile to try to do someday. = try to recover ... ----wordy

强调衣服被叠得平整，非’叠‘的动作很平整。

workstation的厂家想降价来给采购带来好处interest。
要求削弱。
这里的buyers for those corporations是公司采购，不是一般的个人买家。

A 对于大多数采购，他们觉得报价低。无关
B 各大厂家的电脑性能都差不多，无关
C 雇了解行情的人当采购，无关
D 投入到workstation上的资源不一样，无关
E 采购拿不到因为谈的采购价远远低于报价的奖金。

句子的整体结构应该是说Medicare covers the full cost of home health care, but (does) not (cover) (the full cost) of other nonhospital services.

A 平行错误；另外，where的用法错误，where引导定语从句的时候，先行词只能是具体的地点名词，排除。
B making beneficiaries pay 20 percent of the costs可以看做伴随状语，修饰整个句子，那么make的主语是medicare，语义不通；也可以看做前面other nonhospital services的后置定语，语义也不通，services本身不能make beneficiaries做什么。
E 同B
D which is unlike other ...如果修饰的是前面的home health care, 意思就成了home health care is unlike other nonhospital services in that ...，两个事之间没有因果关系，又或者一般我们会讲“A不像B，A怎么着怎么着”，不会讲“A不像B，B怎么着怎么着”？

(d) "the possible VERBing" is inferior to "possibly VERBing".
"and" doesn't make sense in context (it makes it seem as though the two effects must occur together); "or" makes more sense.

in general, ACTION NOUNS (adoption, destruction, etc.) don't imply that the subject of the sentence is performing the action; they usually refer to the general notion of that action.
by contrast, -ING forms do usually imply that the subject of the sentence is the actor.

here are two simpler sentences to illustrate:
i want to learn about adopting dogs --> implies that i actually want to adopt dogs myself.
i want to learn about the adoption of dogs --> i want to learn about dog adoption in general, but there is no implication that i actually want to adopt any canines into my own home.

"amount" is a construction that can only be used to refer to UNCOUNTABLE quantities -- i.e., continuous quantities / mass nouns, which are not divided into distinctly countable units.
for instance, you can have an "amount" of water, furniture, etc., but you CANNOT have an "amount" of people, items, etc.

this sentence is very clearly speaking about a countable quantity -- the number (not "amount") of drive-in theaters. since that's countable, any choice with "amount" can be eliminated immediately.

Ron:"twice as many", "one-quarter as many", etc. are not only acceptable as idiomatic expressions but also extremely common in the english language.
since this idiom is present in the correct answer, which was written by gmac, IT IS CORRECT.

In general, you won't need the second half of that construction if you have already mentioned the data elsewhere in the sentence.
the earlier part of this sentence already mentions the # of drive-ins in the u.s. in the 1950's, so it is not stated again. since it is not stated as part of an actual parallel construction, you don't need the second "as".
--
examples:
there were once 20 shirts on this shelf, but, now, barely half as many are left. --> i already mentioned the data (i.e., 20 shirts) earlier in the sentence, so it's not mentioned again.

there are barely half as many shirts on this shelf [i]as there were last week.[/i] --> i didn't mention this comparison point earlier, so i'm mentioning it now.

xxx industries that are clean and (are) fast-growing and (industries) that pay good wages to xxx

slackening is influenced less by gov regulation than by another thing.

十位数调动总和会变，个位数调总和不会变

Think about it this way: x Difference between y and x is more than 5 so it is at least 6. But x is even and y is odd so their difference would be odd. Hence the diff between them will be at least 7.
Now z is greater than y by at least 2 (since z is odd too), hence diff between x and z is at least 9.

D. 主干变成了：(与environmentalists' proposals不同的是,) administration's proposal was a call. 错误

against concluding that the oceanographers' hypothesis is false，反驳他的假设是错的，就是支持他的假设