Here are the completed sentences:

1. Ellen wants to become a doctor in the future, **so** she's going to a medical school.
2. Sophie is going to a special school for musicians, **because** she wants to become a professional pianist.
3. My friend wants to be a doctor, **but** I want to be a teacher.
4. I didn’t get the job, **but** I’m going to keep looking for other opportunities.
5. He enjoys working with computers, **even though** he doesn’t have much experience.
6. I can work in the morning, **or** I can work in the evening.
7. Anna needed some money to buy her mom a birthday present, **so** she took a part-time job.
8. The waiter was not very nice, **but** the food was delicious.
9. Julie has a guitar, **and** she plays it really well.
10. I tried my best **but** I could not solve the puzzle.