小题1:He taught in this school last year.(把last year改为 since last year) He _________ _________ in this school _________ last year. 小题2:They didn’t clean the classroom yesterday.(改为被动语态) The classroom _________ _________ yesterday. 小题3:We have already returned the books.(改为否定句) We _________ __________ the books ___________. 小题4:Rice is grown in China .(划线部分提问) _________ is rice ___________?