They're in the classroom doing thier homework.为什么要用doing ,能否

They're in the classroom doing thier homework.为什么要用doing ,能否 they are doing their _____(homework) in the classroom Bill is in the classroom,doing( )homework They're doing homework.问句 (When i was doing my homework in the classroom),they went ou Many boys is doing them homework in the classroom.改错 Bill is in the classroom.doing 什么homework they sat in the room _____ doing their homework. They can't have been doing thier homework.have been 是现在完成时,但 they need to be out in the wild doing 为什么用doing 不用to do He id doing his homework in the classroom now.(改为一般将来时） when i saw him,he was doing his homework in the classroom 同义