i was listening to the radio when the telephone rang
问题描述：
i was listening to the radio when the telephone rang
(改特殊疑问句）—— —— —— —— when the telephone rang ?
the film was on half an hour ago.(改为同义句)
the film —— —— ——for half an hour
答
What were you doing
has been on
第一句是was吧人称改为第二人称了， 所以be 动词也要作相应变化