核心问题
（1）I've loved you as if you were my son.
(2) He looked as though he were from the country.
as if 与 as though 在意义和用法上有无区别?
词典解答
许多语言学家都认为 as if 与 as though 在语义和用法上并没有什么区别。但是在口语中使用 as if 的情况较多。在 A Comprehensive Grammar of the English Language 中把 as if 和 as though 当作一个词条来处理。当然，从修辞上讲，存在着使用哪个形式更合适的问题。但是，这个问题已超出了我们的讨论范围。