time bomb 計時炸彈

time bomb
繁：計時炸彈
简：计时炸弹

另外，港大感染及傳染病中心總監何栢良說，上月有到私家醫生求診的個案，都有呼吸道感染病徵，他擔心當中有未辨別到的確診者，會成為社區感染的計時炸彈。

何栢良憂未識別確診者或成社區感染計時炸彈（2020年4月7日）。rthk，取自https://news.rthk.hk/rthk/ch/component/k2/1519306-20200407.htm

Ho said he was worried that a considerable number of people carrying the virus go undetected, becoming a “time bomb” for infections.

More private docs wanted for virus hunt. (2020, April 8). The Standard. Retrieved from https://www.thestandard.com.hk/section-news/section/4/218004/More-private-docs-wanted-for-virus-hunt