问题补充：
The TV play for ten minutes when I turned on the TV.
A. had started
B. had begun
C. has been on
D. had been on
答案：
A. had started
B. had begun
C. has been on
(答案→)D. had been on
解析：句意：当我打开电视的时候，电视剧已经演了十分钟。因为是在我打开电视的时候，所以是过去的过去，所以要用过去完成时。时间状语是for ten minutes，所以要用延续性动词。上映的延续性动词是be on。故选D.
