A theory should be internally consistent.

一套理论应当内在一致。

《柯林斯英汉双解大词典》

It was a theory unsupported by evidence.

这是一条没有证据支持的理论。

《柯林斯英汉双解大词典》

It's only a theory, admittedly, but the pieces fit together.

得承认这只是一种理论，但其各部分自成一体。

《柯林斯英汉双解大词典》

In nineteen eighty-two, American researchers James Wilson and George Kelling wrote a report describing what they called the broken windows theory.

VOA: special.2009.03.03

And he has a theory about early life and perfectly appropriate as far as one can tell of what pre-human form he studied.

他有一个有关早期生命的理论,一般人都会觉得很正常,他研究人类之前的生命形式没有什么不合适。

普林斯顿公开课 - 人性课程节选

He urged revival of the slave-trade in the late 1850s, and he developed a theory of what he called warranteeism--w-a-r-r-a-n-t-e-e-I-s-m.

他促成了十八世纪五十年代后期,奴隶交易的复苏,还自己发明了一套理论,名为抵押品主义

耶鲁公开课 - 美国内战与重建课程节选

This notion was revived in the 1950s, when the building of a genuine chess-playing machine was seen by artificial-intelligence researchers as a stepping-stone towards a general theory of machine intelligence.

ECONOMIST: Computers and chess

After orchestrating 2 million collisions between lead nuclei and protons, like the sort you see above, the collider's Compact Muon Solenoid group and researchers at MIT suspect that stray, linked pairs of gluon particles in the mix were signs of color-glass condensate, a currently theory-only form of matter that sees gluons travel in liquid-like, quantum-entangled waves.

ENGADGET: Large Hadron Collider may have produced a previously undetected form of matter

While his report is fully supportive of the move to degree-level training, it has acknowledged there is a "theory-practice gap".

BBC: Don't forget tomorrow's nurses