Complete the sentences. Use the correct form of the Present Perfect or Present Perfect Continuous Tense. 1. He... (to be) in boxing since he was 9 years old. 2. My classmates already (to know) some amazing facts about Ukrainian sportsmon. 3. They (to play) volleyball for an hour. 4. Bill (to play) baseball before. 5. John can't participate in the competition because he... (to break) his arm 6. We (to train) in the Sports Centre for three years .