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?)