When we were having our supper,Tom came in

When we were having our supper,Tom came in when the guest arrived.we were having our supper.为什么不能用as so one day,we were having lunch when a foreign boy came( )our c we were our papers carefully when Tom handed his in We were having supper when the phone rang 改否定 We were having supper when the clock ________ twelve.(Unit10 when we were having maths class,the door opened and in came ( )we were having breakfast,he came in.A.while B.when C.afte We were having supper when the phone rang为什么不可以说We had suppe yestoday evening they were having their supper a guest came We were having fun in the playground when the bell We were having so much fun that when lunchtime came.mother a