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？