These methods prevent pregnancy.

这些方法预防怀孕。

Further treatment will prevent cancer from developing.

进一步治疗将预防癌症恶化。

We recognized the possibility and took steps to prevent it happening.

我们认识到这一可能性并采取行动预防其发生。

He said this would prevent companies from creating new jobs.

他说这将阻止各公司创造新的职位。

Its nationals may be prevented from leaving the country.

其公民可能会被阻止离开该国。