yawning

n.打呵欠

adj.裂开的；打哈欠的

动词yawn的现在分词形式.

Yawning is a sign that you are sleepy or tired. 打呵欠表示你困了或是累了。

The researchers found that those who breathed through the nose rather than the mouth were less likely to yawn when watching a video of other people yawning. 研究人员发现，在看别人打呵欠的视频时，用鼻子呼吸的人比用口腔呼吸的人打呵欠的几率要小。

Although we associate yawning with sleepiness and boredom, its function appears to be to wake us up. 虽然我们把打哈欠与睡意和厌倦联系在一起，但打哈欠的作用似乎是使人清醒。