---Will you please stay here a little longer?
---Sorry, I . I eat dinner with my mother. She’s ing.
A. mustn’t; will have to
B. don’t; have to
C. can’t; had to
D. can’t; will have to
网友回答
A. mustn’t; will have to
B. don’t; have to
C. can’t; had to
(答案→)D. can’t; will have to
解析：AB选线助动词用法有误，从下文来看应是将来时态，所以选D。