By the time John ________ the destination, he ________ for about three hours. A. will get / has walked B. gets / will have been walking C. has got / walks D. is getting / is walking
By the time John ________ the destination, he ________ for about three hours.
A. will get / has walked
B. gets / will have been walking
C. has got / walks
D. is getting / is walking