Rewrite the sentences using because of. Make any necessary changes.

1. I couldn't play because my arm was broken.
   I couldn't play because of my broken arm.
2. Teresa got the job because her exam results were good.
   
3. The weather was terrible, so we couldn't eat outside.
   
4. As she had a cold, she didn't go to school.
   
5. The light was bad, so the referee stopped the game.
   
6. The traffic was terrible; I was late.
   
7. He's only 17, and therefore he can't vote.