11. advice
12. solar
.
15. effective
Ex 2
1. She wasn't beautiful, but she took part in beauty contest.
2. Since it was raining, we decided to postpone our camping.
3. She suggests they singing a song.
4, As she was ill, she couldn't come to class.
5. She was busy, so she couldn't join us.
6. As she had a lot of difficulties, she managed to sell the house.
7. They suggested we leaving the place at once.
8. As it is raining, I stay at home.
9. She wanted to go home because she was tired.