Although, through, even though and even though both mean "although, even though", although and although the tone is weak (through is more popular than although, less formal than although), even though and even though are more emphasized. For example: Although they are poor, they are happy. Although they are poor, they are happy. //Although it was cold, he went out without a coat. Although it was cold, he went out without a coat. //Although they may not succeed, they will still try. Even though they may not succeed, they still try hard. //Although this article is short, it is very important. That article is short, but it is very important. //He's better, though he hasn't recovered yet. He's better, though he hasn't recovered yet. //Although it was raining, she walked to work. Even if it rains, she walks to work. //Even if I can only stay for a few minutes, I will visit him. I'm going to visit him tonight, which means.

So I can only stay for a short time.

Note: The usage of adverbial clauses guided by though is quite special. It can be inverted or not. For specific usage, please refer to the usage of adverbial clauses guided by as.