though，although引导让步状语从句时，后面的主句不能有but，however，但是可与yet，still连用。

1. although和though同义，在一般情况下，可以互换使用。只是though较普遍，常用于非正式的口语或书面语中，而although则较为正式。另外although语气比though重，常用以强调让步概念。
e.g. Though/Although my car is very old, I don't want to buy a new one.
同义句：My car is very old, but I don't want to buy a new one.
虽然我的汽车很旧，但我不想买一辆新的。

2. even能和though组合表示强调，但even不能和although组合。因此，不能说even although,在这里even though=even if(no matter if; though即使……也……)
e.g. Even if/Even though we could afford it, we wouldn't go abroad for our vocation.
即使我们付得起这笔钱，也不出国度假。

3. 当让步状语从句指某种假设情况时，通常用though,而不用although。
e.g. Though all the world were against me, I should still hold to my opinion.
就算全世界都反对我，我还是坚持我的立场。

4. though可以独立用作副词，常放在句末，意为all the same (还是；仍然)或however(可是；然而)，而although无此用法。
e.g. She didn't tell me what she had done, but I know it though.
她没有告诉我她所做的事情，但我还是知道了。 

5. although和though引导让步状语从句时，常采用省略形式。
e.g. Although tired (=Although he was tired), he kept on working.
虽然很疲劳，但他继续工作。