keep a straight face
成語所屬單字straight-faced
keep a straight face — 慣用語
1. to stay serious and not smile or laugh, even though you find something amusing.
1.慣用語
釋義
忍住不笑；板著臉
to stay serious and not smile or laugh, even though you find something amusing.
例句
Chidi somehow kept a straight face while his boss yelled at him for the broken computer.
It was hard to keep a straight face when Rania announced she was the queen of the kitchen.