问题补充：
If there no buying and selling of animals, there no killing in nature.
A. is, will be
B. will be, will be
C. is, is
D. will be, is
答案：
(答案→)A. is, will be
B. will be, will be
C. is, is
D. will be, is
解析：句意：如果没有买卖动物，大自然将没有杀害。if 引导的条件状语从句主句用一般将来时，从句用一般现在时表示将来，there will be表将来，故选A
