Only if enough evidence is discovered in the existence of the monster.A. will people beli

问题补充：

Only if enough evidence is discovered in the existence of the monster.

A. will people believe

B. people will believe

C. shall people believe

D. people shall believe

答案：

(答案→)A. will people believe

B. people will believe

C. shall people believe

D. people shall believe

解析：句意：只有足够多的证据被发现，人们才会相信怪兽的存在。only所修饰的副词、介词短语或状语从句位于句首时，要用倒装语序。故选A.