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。

"Yawning is a really big deal," Provine said.

“打哈欠是一件大事，”Provinice认为。

"That's my candidate for the most ancient joke," Provine said.

“这是我作为候选的最古老的笑话，”布诺温说。

Figure 1. Sampling Route Figure 2. Crop growing curve in Hebei Provine.

图一。 华北、东北空间采样路线图二。 河北作物长势图。

In other experiments, Provine has proved that yawning has nothing to do with oxygen or carbon dioxide intake.

在其他的实验中，普罗万也证明打哈欠与氧气或者二氧化碳的吸入没有关系。