Fill in the blank with one verb to complete the sentence.
1. If you don’t have enough training, you may get injuries when you ... ice skating.
2. Peter is the best player in his baseball team but he doesn’t want to ... for any competitions.
3. When you swim ... , your arms and your legs will move somewhat like a frog swimming in the water.
4. A: Why do you like ... karate?
B: Because it helps to build my muscles and improve my mood.