The bell for the writing class rang and all(both 改为all） the students had taken seats, waiting（wait 改为waiting, 表伴随）for the teacher to arrive. Several minutes have passed（加have), but the( 特指该老师，加定冠词the) teacher didn’t appear. We began to wonder what had（注意时态，have改为had） happened to her. Some students began to talk while（注意when和wh...
