[讨论]OG46 关于时态

OG46

为方便，我直接把正确的句子抄下：

A study commissioned by the Department of Agriculture showed that if calves exercise and associate with other calves, they require less medication and gain weight more quickly than those raised in confinement.

a study showed是过去发生的动作，而其内容calves......是一般存在的规律。