问题

_____ football on tin playground, Ifound ‘my keys ______
A:thedoorbell rang
B:weheard the doorbell ring
C:therewas someone knocking at the door
D:weheard the doorbell rung
B:weheard the doorbell ring
C:therewas someone knocking at the door
D:weheard the doorbell rung
正确答案是: