5.Choose the right tense form.1. Nina has been learning/has learned English for 2 years.2. The birds have already flown/have been flying to the South.3. They have known /have been knowing him for many years.4. Mike has forgotten/has been forgetting to learn the poem.5. The children have been watching/have watched cartoons for 2 hours.6. The train has just come/has been coming.7. We haven’t been having/ haven’t had a holiday for 5 years.8. She has been teaching/has taught at this school for twenty years.9. David has been painting/has painted in his studio since 10 o’clock.10. Mary and Sam have collected/ have been collecting stamps for 3years.11. Their parents have been/have being friends since their childhood.12. Dave has been/ has been being a student for 2 years.