打哈欠常易于感染.用英语怎么说？

打哈欠常易于感染.

Yawning is often contagious.

yawning

n. 打呵欠；adj. 张着大嘴的，打哈欠的；v. 打呵欠( yawn的现在分词 )，张开，裂开；

例句
...the yawning gulf between her fantasies and the tawdry reality.
她的幻想和冷酷的现实之间的巨大差距

is

vt.& vi. 是（be的三单形式；n. 存在；

例句
Bollinger 'RD' is a rare, highly prized wine.
博林格RD香槟是一种名贵的备受推崇的葡萄酒。

often

adv. 常常，经常，时常，再三；

例句
Genetic abnormalities are more often associated with faults in paternal DNA than in maternal DNA.
相对于母本DNA,基因畸变往往更多地与父本DNA上的缺陷相关。

contagious

adj. 有传染性的，传染病的，有感染力的，会蔓延的；

例句
...a highly contagious disease of the lungs.
极具传染性的肺病