他犯了个大错，结果丢了工作。

He made one big mistake, and, as a result, lost his job.

《牛津词典》

他们犯了个大错，认为他们可以用相对少的军队占领边界。

They made the big mistake of thinking they could seize its border with a relatively small force.

《柯林斯英汉双解大词典》

因为缺钱，他犯了个大错。

He is short of money. He has made a big mistake.

youdao

People tend to want to rush in and do this right away.

人们通常都很着急的去做集成测试,这通常来说是个犯了个大错。

麻省理工公开课 - 计算机科学及编程导论课程节选