By the time Jhon gets home,her anut for London to attend a meeting.A will leaveB leavesC will have leftD left

问题描述:

By the time Jhon gets home,her anut for London to attend a meeting.
A will leave
B leaves
C will have left
D left

选C.
by the time表示到那时/到……的时候,出现时主句常用完成时.
至于John gets home用一般现在时,是和when有点相像的,表示将来的一个情形.