我最近在reddit发布了一则英文笑话，但是外国人似乎看不太懂，谁能告诉我该如何需修
改？感谢啦。
On the metro,there was a couple sitting in the priority seat. An young girl ca
me and said to the man,"I'm pregnant." His girlfriend was stunned,slapping him
. In the meantime,the young girl said,"I'm pregnant. Can you yield the seat to
me?"