她用一脸严肃的表情讲了个冷笑话，这种面无表情的幽默反而让全场大笑。

Her deadpan humor, delivered with a completely straight face, made everyone burst into laughter.

deadpan 是由 dead（死的、无生命的）和 pan（平底锅）组成的复合词，字面意思是"像死掉的平底锅一样毫无生气"。 deadpan 作为形容词或副词，用来形容"故意面无表情地说话或表演"，这种反差反而能产生幽默效果。