1. She can't work hard because she is very old.

2. Because of her beauty, he likes her.

3. He was very poor so he couldn't go to school.

4. I can't buy this bike because I don't have enough money.

5. Because of his carelessness, he broke the vase.

6. Because he didn't learn the lessons carefully, he failed the exam.

7. Because of heavy rain, we can't go for a walk.

8. He left school because his life was hard.

9. Because she was given a new bike, she was very happy.

10. I felt tired so I went to bed early.