Question

1. While he is poor, he is very happy.

2. Although he is poor, he is very happy.
3. Though he is poor, he is very happy.
(Are the three the same in meaning?)

4. He is friendly, while his brother is unfriendly.
5. He is friendly, but his brother is unfriendly.
6. He is friendly. However, his brother is unfriendly.
(Are the three the same in meaning?)

Answer 1

They all mean the same. #6 would be better as one sentence, "...friendly, however. his..." The "rules" of English grammar say it's not proper to begin a sentence with a conjunction (and, but, however, etc.), but we do it all the time.