Объяснение:
1. My friends waiting for a bus for ten minutes only.
2.Ben reads this book for three days.
3.She cleans the flat more than a hour.
4.Peter swims for half an hour.
5. Anna speaks on the phone for an hour now.
6.They are playing basketball for twenty minutes.
7. Nelly and Mary doing the shopping since early morning.
8. It is snowing since last night.
9. Jack and his friend riding bikes for three hours now.
10. The teacher explains a grammar rule since the beggining of the lesson.