He thought that if he couldn't see something, it didn't exist.

他认为如果他看不见某种东西，它就不存在。

《柯林斯英汉双解大词典》

Like an ostrich, she thought that if she couldn't see me, then I don't exist.

就像只鸵鸟一样，她以为如果她看不见我，那么我就不存在。

youdao

youdao

He said that there was no reason to continue writing music as if these devices did not exist.

VOA: special.2009.06.21

That is, if they exist through Darwinian natural selection, ? to what extent can we ever get rid of them?

如果性别差异存在于,达尔文所说的自然选择当中，我们可以消除性别差异吗？

耶鲁公开课 - 心理学导论课程节选

But if the soul is something immaterial, then that could continue to exist, even after the destruction of the body.

但如果灵魂是非物质的,那么它会继续存在,即便肉体已经被分解殆尽

耶鲁公开课 - 死亡课程节选

Shariah compliant finance would not exist if it did not exist to promote shariah.

CENTERFORSECURITYPOLICY: Center For Security Policy

If wormholes exist, they could be adapted to make time machines that send you into the future if you traverse them in one direction, but into the past if you go in the other direction.

CNN: Time travel: Can it really be done?

If they exist I think it is safe to conjecture they would be in the vast minority.

FORBES: Reputable Conservative Economists Recognize the Danger of the Debt Ceiling