You can't tell for certain that a number is prime without trying to factor it, but you can apply a number of simpler tests that will verify its primeness to any degree of certainty that you want.

你不能没有试着分解某个数就肯定地说这个数是质数，但是你可以使用大量的简单测试在某种你需要的程度上确认它是质数。

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The mechanism of phase modulation is investigated based on the model of two degree of freedom in the thermoacoustic prime mover consisting of a looped tube and the resonator.

基于环形圈加谐振管的热声发动机的两自由度模型构思，在调相机理上开展了工作。

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Mr. Page was found guilty of first-degree murder and was a prime candidate for the death penalty.

WSJ: Neurocriminology: Inside the Criminal Mind

But it also seems deeper when there is a degree of ideological convergence between prime minister and president.

ECONOMIST: Mr Blair goes to Washington

George Papandreou, Greece's Socialist prime minister, can count on a degree of understanding from half the electorate (not all of them voters for his party) that the country faces a make-or-break moment in which wrenching change is the only alternative to outright disaster.

ECONOMIST: The Greek crisis