6. You ………………………………… (wait) for a bus for ten minutes only.
7. Nelly and Mary ………………………… (do) the shopping since early morning.
8. It ……………………………….. (snow) since last night.
9. Jack and his friend ………………………………. (ride) bikes for three hours now.
10. The teacher …………………………………… (explain) a grammar rule since the beginning of the lesson.
II. Сделайте эти предложения отрицательными.
III. Сделайте эти предложения во