the technique is electron paramagnetic resonance spectroscopy,

这里用到了电子顺磁共振波谱学技术
shows that in truth, although this is two species,

它证明即便上面这两个式子是不同的
this is one species.

下面这两个其实是同一个东西
So there's equilibrium at the top and resonance at the bottom.

上面的式子是平衡而下面是共振
And if you add an extra electron to make a carboxylate anion,

如果再加一个电子形成羧酸阴离子
infrared spectroscopy tells you that it's symmetrical too.

红外光谱表明它俩还是一样的
There's resonance in this case.

这就是共振
It's an intermediate structure.

是一个处于中间的结构
But that is "lore."

不过这属于经验知识
You didn't predict that from Lewis structure ahead of time.

你无法由路易斯结构预测到它到底为何
It could've been either way, and in fact

它既可能是共振也可能是平衡
there were many people who thought it was one way or the other.

事实上大家都可以有不同的看法