Robert Frank once made this comment about his work: "I am always looking outside, trying to look inside, trying to say something that is true.

VOA: special.2009.03.23

Some of those instructions will involve tests: they'll say, is something true?

有些指令需要包括测试：,他们会说，这个东西是真的么？

麻省理工公开课 - 计算机科学及编程导论课程节选

So if you wanna do something conditionally, you generally needs to ask the question, is the following true or false.

假如想在一定条件下做一件事情，你需要判断下这个条件，来看看条件是真还是假。

哈佛公开课 - 计算机科学课程节选

It is merely a matter of applying an agreed-upon set of rules (for instance, that any thing is equal to itself, or that if something is true for all members of a set of objects, it is true for any one specific object) to a set of agreed-upon structures, such as sets of objects.

ECONOMIST: Just what does it mean to prove something?

"The notion of a 'graveyard of empires' is actually a false extrapolation from something that is true -- that there is tactical and strategic difficulty, " Porter says.

CNN: Is Afghanistan really a 'graveyard of empires?'

And it's just - it's important to try to sort out all that rhetoric and really just get down to whether something is true or not.

NPR: Political Ads May Not Tell Whole Story