新概念3有个句子不太明白

Question

experts confirmed that a puma will not attack a human being unless it is cornered. 为什么这里will不用过去式啊
The experts were now fully convinced that the animal was a puma 这个句子你看都用过去式

Answer 1

a puma will not attack a human being unless it is cornered 这个是当作真理，客观事实，所以不用改变时态。对所有的 puma 都适用。

that the animal was a puma 这个只是对那里出现的一个动物，不是普遍适用的真理。所以用一般过去时。

Answer 2

experts confirmed that a puma will not attack a human being unless it is cornered.
这里a puma will not attack a human being unless it is cornered阐述的是客观规律，不需要改变时态。本回答被提问者采纳