Contagious yawning

打呵欠是否會傳染﹖（Is yawning contagious？）科學家相信會的，而且人類自四歲起便發展出這項本能。科學家認為看到別人打呵欠，自己也不禁打呵欠是同理心的表現，可以促進微妙的感情聯繫。

因為感到疲倦而打呵欠，所以要配合伸懶腰，伸展一下筋骨。英文可以說He stretched himself with a yawn.或者He stretched and yawned.（他伸了伸懶腰，打了個呵欠。）

打呵欠又或因為沉悶無聊，悶得不由自主地打個呵欠，可以說couldn't help yawning或can't stop yawning。例句：We couldn't help yawning during the 3-hour lecture.（講課長達三小時，我們忍不住打呵欠。）I can't stop yawning during the day.（我白天不停打呵欠。）

口語yawn可以指「乏味的事情」。例句：That musical was just one big yawn from start to finish.（那音樂劇從頭至尾都極其乏味。）We have to go to a party this Friday night with the boss which is a bit of a yawn.（我們周五晚上要跟老闆一起去派對，真是有點乏味。）