邻国入侵的威胁持续存在。

There is a constant ___threat of invasion from neighboring countries.

核武器的威胁自此已发展成一种常态。

The ___threat of nuclear weapons has since grown into a constant condition.

气候变化对全球粮食安全构成严重威胁。

Climate change poses a serious ___threat to global food security.