日期：
来源：雅诚德英语网
If there are no truly non-venomous snakes, were the so-called non-venomous snakes, like constrictors and pythons, were they venomous at some point in their evolution?
如果没有真正的无毒蛇，那些所谓的无毒蛇，比如蟒蛇和巨蟒，在它们进化过程中的某个阶段是有毒的吗？
If there are no truly non-venomous snakes, were the so-called non-venomous snakes, like constrictors and pythons, were they venomous at some point in their evolution?
如果没有真正的无毒蛇，那些所谓的无毒蛇，比如蟒蛇和巨蟒，在它们进化过程中的某个阶段是有毒的吗？