Provine realized that the reason chimps cannot emit a string of "ho ho ho" is that they cannot make more than a single sound when they exhale or inhale.

普罗文认识到，黑猩猩之所以不能发出一连串的“呵呵呵”声音的原因，在于它们在呼气或吸气时无法发出一个以上的音节。