Это упражнение на порядок слов в английском языке и на использование вспомогательных глаголов.
Ответ: 1. Jane is listening to music; 2. Alex plays computer games; 3. Julia visits the doctor; 4. Is the baby sleeping?; 5. Are the children singing?; 6. My mother cooks dinner; 7. We often watch English films at the lessons; 8. My mother is talking to her friend now.