although 和 though 用法上有何分別？

although and though are both conjunctoins. But sometimes though can be use as an adverb:

'Snow is not predicted; we can expect some rain, though.'

[from dictionary.com]

they are very similar to each other. As conjunctions, although and though are generally interchangeable: Although (or though) she smiled, she was angry. Although is usually placed at the beginning of its clause (as in the preceding example), whereas though may occur elsewhere and is the more common term when used to link words or phrases, as in wiser though poorer. In certain constructions, only though is acceptable: Fond though (not although) I am of sports, I'd rather not sit through another basketball game.

"Although " and "though " are all adverbs of concession. They are used to connect two clauses which we would not expect to be together. They are always followed by a clause, but they can be used at the beginning of a sentence or in the middle position:

eg. Although the weather was very bad, they still went fishing.
(the weather was bad so we would not expect them to go fishing)

They didn' t catch anything, though they fished all day.

"Although " is more informal than "though ".

although and though have the same meaning and they both serve as the function of a conjunction.
e.g. although i am young, i am independent (=i am independent although i am young).
e.g. though i am young, i am independent (=i am independent though i am young).

however, though can also serve as an adverb.
e.g. the project is hard, i will do it though.