改为一般疑问句：The meeting has been on for fifteen minutes.

改为一般疑问句：The meeting has been on for fifteen minutes. The meeting has been on for fifteen minutes.改为同义句 the film has been on for fifteen minutes The film has already been on for ten minutes 变一般疑问句 The meeting has been on for half an hour.（改为同义句） The meeting 4题英语,帮个忙,1.The film has been on for twenty minutes.(用begin改为 The flim has been on for 30 minutes同义句 The film has been on for five minutes是什么意思 Mary has been playing the guitar for two hours.(改为一般疑问句) --- the class -t-for 15 minutes.A:has begun B:has been on The meeting ______just for several minutes.A.has begunB.has 请问：the meeting has been on for over ten mimutes.中为什么加ON?