He mistakenly believed that his family would stand by him.

他误以为他的家人会支持他。

《牛津词典》

He says they mistakenly believed the standard licences they held were sufficient.

他说他们错误地以为持有标准许可证就足够了。

《柯林斯英汉双解大词典》

Students sometimes mistakenly assume that the section contains literature books.

学生们有时会错误地认为这个部分包含了文学书籍。

youdao

And,about sixty percent mistakenly thought the sun was generally good for one's health.

VOA: special.2010.07.06

It's a widely--it is widely and mistakenly thought that the purification offering purifies the sinner or the impurity bearer or the offerer. This can't be true.

很多人错误得认为,净化祭可以净化不洁者或供奉者,身上的罪孽或不洁，事实并非如此。

耶鲁公开课 - 旧约导论课程节选

It's best if you don't know what that is or even if you do mistakenly attribute it, misattribute it, to physical attraction, romance, intimacy, passion and commitment, it's love.

最好是如果你不知道是什么,甚至如果你错误认定，以为是生理吸引力，浪漫，亲密，激情和承诺，那是爱情。

耶鲁公开课 - 心理学导论课程节选

The daughter of a writer, Rufina was mistakenly pronounced dead on her 19th birthday following a cataleptic attack.

BBC: The Recoleta Cemetery: Silent theatre and city of the dead

Doctors not familiar with ciguatera sometimes mistakenly give a diagnosis of chronic fatigue syndrome.

BBC: Fish food poisoning breakthrough

America's misguided Treasury Department mistakenly believes a cheaper dollar will mean a better trade balance.

FORBES: Fact and Comment