--- 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

—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

 — 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

--- Who do you think ___ the book here? 

--- It may be John. He was sitting here all the morning.

1. A.
   was leaving
2. B.
   leaves
3. C.
   had left
4. D.
   has left