C，不能用as in other countries的原因是：前面是个否定句，never evolved，谓语动词完全省略，意思会变成Linking arrangements never evolved in USA as (they never evolved) in other countries.
Linking arrangements never evolved in USA as they did in other countries，did指代evolved，则不会有歧义。
同样的例子还有：The scientists would have to know more about the problem than they do now. 如果省略they do，than now，会变成have to know more than they have to know now,但现在做的并不是have to know，不得不了解，二是已经了解。
谓语动词能否省略，取决于将前面句子谓语动词+谓语动词的时态/语态继承过来以后，被省略句子是否逻辑合理。
among/between
among 用于三者或三者以上的“在…之间”，其宾语通常是一个表示笼统数量或具有复数(或集合)意义的名词或代词。among通常不与and连用。如：
He is the youngest among the wealthy .
My grandparents are traveling among a group of tourists.
between指在二者之间，有时与and 连用
There is a river between us。我们两个人之间隔着一条河。
include本身是动词，可以单独做谓语，只是“，including”是定语而不是伴随状语是一种特殊用法。如：
The tour included a visit to the Science Museum.
Does the price include tax?
Six people were killed in the riot, including a policeman.
也可以用included，如：Many runners, myself included, are loners.
China has a population of 1.3 billion, which is less in USA. 如果是which/where 这种定语从句连接词，则不一定是同物指代，也可以指代名词中的一部分。
如：Electricity is installed in 1 percent of homes, where lighting is mainly provided by candles.这里where指代1 percent of homes里的homes，而不是指代整个名词。
the age of eighteen是一个整体，18做定语，限定age。it指代被18限定的age。
it/they同物指代，整体指代。看it到底指代哪串名词，看名词后是否带了定语。如：
The population in China is 1.3 billion, but the population in USA is much less. in China 做population的定语，后面不能用it指代，来表述美国的人口。
The population is 1.3 billion in China, but it is much less in USA. 这里in China做状语，先行词是the population,可以用it来指代，表述美国的人口如何如何。
C，A fly as many as 20 percent more hours than B,或 A fly as many as 7 more hours than B
fly more hours per month, as much as 20 percent，than B。将 as much as 20 percent看成同位语，补充说明more hours per month，到底more了多少；
as much as 改成as many as,2数字可以指代名词，20%是单数还是复数看它指代的名词是单数还是复数。20% hours是复数。
be dated to X ago; be dated at X old;
to做介词，通常表示方向，接数字时，表示达到某个数值点。如：the revenue has grew to 60 million,增长并且触及到6000万这个点。
X ago是一个时间点，类似于在x ago这个时间点，这个东西啪的一下就诞生了，用to；x old更倾向于是一个状态，用at
原来的情况：weekly income adequate but not always uniform，意味着原来的工作量OK，单价OK，但是收入起伏很大，因为是按照实际工作小时数结算费用，所以个别星期因为家长的原因没有做满小时数的话，收入就下降。
诉求：weekly income both uniform and adequate，意味着不修改每小时的charge rate（排除D）也不额外增加工作量（排除AE），使每个星期的收入比较平稳（C的话还要增加资本投入，无助于使收入平滑），B就很明显了，跟客户报个打包一口价，预计一周40小时每小时X元，你因为各种原因不送孩子来不关我事，我也收40X元
Halley's comet cause such a worldwide sensation In no other historical sighting as in its return in 1910–1911
=Halley's comet doesn't cause such a worldwide sensation In any other historical sighting as in its return in 1910–1911。
其实是一个not such/as的比较结构，因为前面的比较对象带了比较的范围，所以后面的被比较对象可以省略，只保留范围状语。
扫描二维码，直接登录
主语和谓语动词能否省略，只保留时间/范围状语等，取决于将前句的谓语动词+谓语动词的时态/语态/肯定否定式平移过来后，被省略句的逻辑是否合理。特殊情况：如果前后都有时间状语，比较不同的时间下的情况，可以省略主谓只保留时间状语，不管时态是否一致。