（1）though 可以用作副词，作“但是”解。但 although 不可，如 He said he would come, he didn't, though 里的 though 不可改作 although。
（2）as though 中的 though 不可改作 although。参见 as 18
（3）although 比 though 正式而语气重，不及 though 通俗。
（4）although 所引导的从句，通常指事实而不指设想，如下面第一句里用 though，第二句里用 although：
He would not be unhappy though he should have to live alone. （他即使不得不独自居住也不会不快乐。）
He was not unhappy although he had to live alone. （他虽然不得不独自居住，却并不不快乐。）
下面两句里的 though 不可改作 although：
Let's not defer the trip though it rain (不用 rains) tomorrow.
Though everybody desert (不用 deserts) you, I will not.
图片发自简书App
图片发自简书App
