His fists clenched slowly until his knuckles were white.

他的拳头慢慢地捏紧，直捏得指关节都发白了。

《牛津词典》

Out jumps a muscular Kyrgyz man, his fists clenched.

从车上跳下一名五大三粗的吉尔吉斯男子，双拳紧握。

youdao

I remember seeing arsene Wenger rise from his seat, both fists clenched, his face working.

我依然记得温格从他座位上跳起来，两个拳头紧握，他的脸部表情很激动。

youdao

"He turned towards me, he had both fists clenched... grinding down on his teeth, " PC Milby said.

BBC: Dale Burns inquest: Officer fired Taser 'out of fear'

Merthyr is a fine place to raise a boxer - Thomas claimed that children born in the tough valleys town were so angry that they came out with their fists clenched.

BBC: 5. Howard Winstone

He was told he would be arrested for criminal damage as the bathroom toilet, extractor fan and light fitting were broken, but became aggressive and approached one of the officers with his fists clenched.

BBC: Dale Burns