问题补充：
He the book to the library if he it tomorrow.
A. returns; finishes reading
B. will return; will finish to read
C. will return; finishes to read
D. will return; finishes reading
答案：
A. returns; finishes reading
B. will return; will finish to read
C. will return; finishes to read
(答案→)D. will return; finishes reading
解析：在if 引导的条件状语中，如果主句为一般将来时，从句用一般现在时代替将来时，故选答案为D
