“定时炸弹”常见的英文表达是 time bomb（也可写作 time-bomb ）。
例如：
There is a time bomb hidden somewhere in the building, and we must find it immediately.（大楼里某处藏着一颗定时炸弹，我们必须立刻找到它。）
The economic crisis is like a time bomb, threatening to explode at any moment.（这场经济危机就像一颗定时炸弹，随时可能爆发。 ）