Hebeintheclassroom,Ithink.No,hebeintheclassroom.Isawhomgohomeaminuteago.A.can,maynotB.must,maynotC.may,can'tD.may,mustn't

Question

He ______ be in the classroom,I think.
No,he ______ be in the classroom.I saw hom go home a minute ago.
A.can,may not
B.must,may not
C.may,can't
D.may,mustn't

Answer 1

,C从I think.看出只是个人的猜测,所以用may.从I saw hom go home a minute ago.,看出非常肯定,所以用can't