The old manin front of the door, waiting
问题:
The old man in front of the door, waiting for his children to come back home.[ ]
A.was used to sit
B.is used to sit
C.used to sit
D.used to sitting
The old man in front of the door, waiting for his children to come back home.[ ]
A.was used to sit
B.is used to sit
C.used to sit
D.used to sitting