When I was at the grocery store,I realized that the prices of many items had been risen.这是改错题,答案是将had been risen改为had been rising.我怎么觉得应该改为had risen呢?因为这里是when,为什么要用过去完成进行时,

when the accident happened,i was just at the s____ at the moment when i was a t__,i was good at playing the piano I remember it was the same when I was at schoolit指的是什么? When I was doing my homework ,I heard someone (knock) at the door. 改错:I was just (falling sleep) last night (when) I (heard) a knock (at) the door. The time when I arrived was late at night.关系副词when 可以改成 at which么? i was watching tv when i heard the door(knocking)i was watching tv when i heard someone(knocked)at the door两个knock形式对吗? When I was in the bathroom sally knocked at the door.错在哪里? I ( ) go out when someone knocked at the door.A.was to B.was going to C.was about to 这是什么从句?that was probably when I was seeing the doctor.---I rang you at about ten,but there was no reply.---Oh,that was probably when I was seeing the doctor.when.开始这句 while he yan was at the doctor's,I was going to the class这里为什么不用WHEN I was studying English when he knocked at the door.改错 The Greens was at table when I vistied them last night.哪里错了 连成句子I,having,when,was,someone,breakfast,at,knocked,door,the 连词成句stopped i car was at the bus waiting stop when When I arrived at the hospital,something strange was happened.这句话有什么错误? He got excited at the news,while I was calm.为什么用while ,不用when Where were you when I ____?I was ____ on the playground.Where were you when I ____?I was ____ on the playground.A arrived at; at play B reached; at play C got; playing D arrived in ; playing