单项选择.-Yesterday I saw Mr.Green walked his dog in the park.
问题描述：
单项选择.-Yesterday I saw Mr.Green walked his dog in the park.
-Yesterday I saw Mr.Green walked his dog in the park.
-Are you joking?It____Mr.Green,he left for shanghai for holiday yesterday morning.
A.can't be B.mustn't be C.may be D.couldn't be
答
D.couldn't be