—Who do you think the book here?
—It may be John.He was sitting here all the morning.
A. was leaving
B. leaves
C. had left
D. has left
网友回答
A. was leaving
B. leaves
C. had left
(答案→)D. has left
解析：
句意为：——你认为是谁把书落在这里了？——可能是约翰。他一上午都坐在这里。强调过去发生的动作对现在造成的影响或结果，应该用现在完成时。