Exercise 1:
1. +He didn't tell me why he'd been late, but I knew it though
+ He didn't tell me why he'd been late, but I knew it nevertheless.
2. Even though it's rather cold, I think I'll go for a walk.
3. Even though she was unattractive, she still had many friends.
4. Unattractive though/as she was, she still had many friends.
5. + They'd lived in London for years. Nevertheless, they always spoke German.
+ They'd lived in London for years. All the same, they always spoke German.
Exercise 2:
1. He may have been brought up in Poland, but he has a perfect English accent
2. She may be a girl, but she plays football as well as any boy.
3. She may be very rich, but she never gives a penny to the poor.
4. I concede that my sister's very intelligent and pretty, but she doesn't have a boyfriend.
5. I grant that he sometimes behaves like a fool, but he's really very intelligent.