Answer the following questions :
1 . Have you bought this book ? 2. when did you buy it ? 3.Have you seen this play ? 4 . When did you see it ? 5 . Have you made this dress yorself ? 6 . When did you make it ? 7. What were you doing at 7 last night ? 8 . were you knitting at that moment ? 9. What were you reading when I entered ? 10. What were you singing when he came ? 11 . Why were you laughing when you saw him ? 12. Why was the baby crying ? 13 . What were you doing when we rang you up ?,14 . What were they writing when the tracher entered ? 15 . What was he listening to when you called him ? 16 . What were you reading when the door-bell rang ?
17 . Where were you doing to when I stopped you ? 18 . Where was the boy running when you saw him?