I CAN'T FIND MY BOOK ANYWHERE. I_______ HAVE LEFT IT ON THE TRA...

15. - File thứ 4: anh12cb_231201916
File thứ 4: anh12cb_231201916

15. I can't find my book anywhere. I_______ have left it on the train. I am not sure.

A. must

B. might

C. should

D. needn't