Fill in the blanks with the appropriate form of "can" or "be able to":
1. When I was a child, I swim very well.
2. Next year, I travel to Japan.
3. She understand the lecture because it was too complex.
4. I finish my homework by tomorrow if I start now.
5. They speak four languages fluently since they were teenagers.
6. Last night, I hear the noise from the street.
7. Tomorrow, you join us for dinner.
8. I come to the meeting next week.
9. He solve complex problems quickly.
10. We maintain good communication despite the distance.
11. She help you if she were here.
12. Unfortunately, they reach an agreement.