问题

Why! I _____ get you on the phone. — We ______ basketball on the playground when you phoned.
A:didn't; must be playing
B:couldn't; must be playing
C:couldn't; must have played
D:didn't; must have been playing
B:couldn't; must be playing
C:couldn't; must have played
D:didn't; must have been playing
正确答案是:
同类题型