我有一种错觉，他要娶我。

I was under the delusion that he intended to marry me.

《柯林斯英汉双解大词典》

有一种错觉是一次做很多事情是富有成效的。

There is an illusion that doing many things at once is productive.

youdao

他们有一种错觉，造币厂觉得这几乎是不可能复制的。

They create an optical illusion that the Mint hopes is almost impossible to duplicate.

youdao

There are philosophers who have said we certainly believe that we've got free will, but it's an illusion.

有这样一些哲学家,他们说,我们确实相信自己有自由意志,但这只是一种错觉

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