straight face片语

不露笑容的表情、绷著的脸、正经的面孔

I could barely keep a straight face during his ridiculous excuse.

他讲那个荒谬的借口时，我几乎忍不住要笑出来。

一本正经地、不动声色地用于 with a straight face

She told the whole lie with a straight face.

她一本正经地把整个谎话讲完。

一本正经的、不露表情的

He gave a straight-faced answer that made everyone laugh.

他一本正经地回答，却让大家都笑了。