网上一本小说的推介文章，老外写的：
This story is originally from 2008, when I wasonly 14 and before I knew the importance of proper grammar. lol.
我的疑问：这句活语法正确吗？when 与 before 从句怎么理解？（有请李翔老师及其他老师）
Following this trend, they conducted explorations into translator's subjectivity in various perspectives as shown in the beginning of this chaptor.
这句话中as后面是否应该加上is形成限制性定语从句?
有本书上说，下面一句中的each other不能换成one another，因为这里是指两者：
The two groups agreed to cooperate with each other. 两个组同意相互协作。
但是，我们老师说过，在现代英语中，指两者也可以用one another，请问哪个说法比较...
请问 than 后面可能接 if 引导的从句吗？比如：If we eat out too often, the cost of living will be much higher than if we eat at home.我总觉得句子中的 than if 用得有点怪。请问这样的 than if 用得对吗？请教各位专家老师！
About $13.2 billion of the estimated $68 billion has been raised through state and federal funds, plus a pledge of cap-and-trade proceeds, or funds paid by companies to offset carbon emissions.疑问：感觉这里用 and 才说得通啊!
Equivalent to x**y (with two arguments) or x**y % z (with three arguments)Some types, such as ints, are able to use a more efficient algorithm wheninvoked using the three argument form.来源;计算机文档
A scene of a public execution and another,where Katniss accidentally steps on a skull, raised the most eyebrows.结合分析一个句子中的过去分词使用（位置）。过去分词有时态意义吗，如何反映时态的？
Chinese consumers smashed last year’s record for purchases on Singles’ Day, the world’s biggest online-shopping frenzy. 请问句中的 purchases 是否可以改为 purchasing？若可以改，改后有何差别？