Cover your mouth when you cough, sneeze, or yawn. ✬

We yawn when we are short of oxygen. ✬

I suppressed a yawn. ✬

Being bored, the audience began to yawn. ✬

They were all so tired that they could do nothing but yawn. ✬

Tom tried not to yawn. ✬

Tom suppressed a yawn. ✬

Put your hand over your mouth when you cough, sneeze or yawn. ✬

Tom gave a big yawn. ✬

Tom is trying not to yawn. ✬