题目里面比较的都是surface mines， 所以E不同不存在。
C用cease来表示20年前和现在的区别，比较隐晦。在时间压力下，比较难发现这个比较。

请问一下后面的some XX of them前面没有加逗号，是做独立主格吗？

You can't memorize this kind of thing as a structure, because structure isn't the issue. The issue is what the sentence means.
In the pair above, the incorrect example is wrong because political situations don't "cause gas prices"; that's nonsense. (Gas prices are not an event precipitated by political events.) In this instance, "increasing" is an adjective.

In the current sentence, the meaning is altogether different.
We're talking about the action of "buying on credit".
In addition, "buying" is the best noun available, because there's no dedicated noun form available (e.g., there's no such thing as, say, "buyage"). By contrast, the noun "increase" is available.

我相信看过Ron视频的同学，对正确答案"Political situations caused a increase in gas prices"（而不是increasing gas prices）记忆尤深，所以这道题也会有点困惑。我搬运一下Ron对于这个的解释，

感觉判断主语有点纠结，之前有道类似的题是rise in price和 rising price，最后是rise。。。

状语是用来修饰动词的特性或特征的

我以为最后一个选项是废话...所以直接跳过...

A选项also前面不应该有逗号吧？

many European countries and the United States conquered high (by these countries' standards) inflation

这道题选项有错误把，C和D是一样的

为什么逻辑上具有相同比率的也不能是人本身...

even if .....
did in fact .....

gmat的CR题是不是特别喜欢提高tolls这类答案。。。prep2012的第一题也是，这两道我都错了，都栽在了过路费上。。。

. One point these journalists overlooked is that in 1997, as in the twenty-four years immediately preceding it, the real GDP per capita grew nearly one-half percent a year more slowly than it had on average between 1873 and 1973.

想问下这里continue to do 和continue doing的区别

求翻译