translation.en: And a final possibility is that there's no relationship at all between learning disabilities and hyperactivity, but that they are caused by a common underlying mechanism in ADHD.
translation.zh: 最后一个可能就是 学习障碍与过度活跃是没有任何联系的， 它们是被一种在多动症中的共同的底层机制所引发的。