1.you were playing showballs after the lessons, 2.you play snowballs every winter, 3.they were doing their homework yesterday after supper, 4.you did your homework after school, 5.they entered the classroom after the teacher, 6.she was writing a letter when you phoned, 7.bob was playing the piano when we came, 8.i'm older than she, 9.he has a sister, 10.sally can't speak chinese, 11.let me call you, 12.tell us about yourself, 13.that was an unusual stone, 14.she hates onion, 15.dan arrived two hours ago, 16.there weren't many students in the hall, 17.the greens have been invited too, 18.don't leave without me,
