although是连词，意为“虽然;尽管”，引导让步状语从句，相当于though。

Although/though We are poor , We are happy.

虽然我们很穷，但我们很快乐。

He often helps me with my English although he is quiet busy.

尽管他很忙，但他还是经常帮助我学习英语。

but是“但是”的意思。在英语中，当句子含有although/though时，就不能再使用but，但可以用yet、still。

Although/Though It was cold outside，he still went out without a coat.

=It was cold outside， but he still went out without a coat.

尽管外面很冷，但他还是没有穿大衣就出去了。