Students breathing pure oxygen did not yawn less than those breathing air with higher than normal levels of carbon dioxide.
呼吸纯氧的学生们并不比那些呼吸比通常水平更高的二氧化碳的人少打哈欠。Serena yawns, stretching her arms over her head, as she pads into the kitchen in her bare feet, where Nate's making nachos.
塞雷娜打哈欠，伸展她的手臂在她的头上，因为她把她的脚裸，在奈特的厨房垫使玉米片。He rubbed his eyes and yawned as though waking up after a long sleep.
他又揉眼睛又打哈欠，好像睡了一大觉刚醒似的。They did not cover their mouths when yawning and were not at all apologetic when they turned up late, he added.
他们在打哈欠的时候不捂嘴，当他们迟到的时候，也不道歉。Frowning, opening and closing of eyes and mouth, chewing, yawning, sleep, dizziness, epileptic seizures in healthy persons were induced.
健康人的皱眉、张开和闭上眼睛和嘴、咀嚼、打哈欠、睡眠、眩晕、癫痫发作被诱发。By mimicking the yawn we become better able to understand how tired, perhaps, or bored the other person is.
通过跟着对方打哈欠，我们能更好地理解和感觉对方有多辛苦，或者说多无聊。Many things connected to yawning, like being tired, make the brain hot, and yawning can reduce the heat, he said.
很多事情都与打哈欠有关，像无聊了啊，让头脑发热，而打哈欠可以减少这种热量。The tiredness theory of yawning does not seem to explain why yawning occurs.
打哈欠的疲惫理论似乎不能解释为什么打哈欠。The bear thought that a very queer name, but he hadn't wondered long over it before he began to yawn and gape, and fell asleep.
熊认为，一个非常奇怪的名字，但他没有不知道长在它之前，他就开始打哈欠和目瞪口呆，睡着了。