The beauty of the experimental design is that it effectively rulesout confounding variables; acoustic isolation assures that the female can respond only to the song structure itself.
实验设计的美妙之处在于它有效地排除了混淆变量；声学隔离确保了雌性只能对鸣声结构本身做出反应。
2
It also means they cannot jump, which rulesout the pirouette.
这也意味着大象不能跳，跳芭蕾就更别想了。
3
But maybe there's nothing in biology that rulesout the possibility.