预警

dì zhèn de yù jǐng xì tǒng

地震的预警系统

earthquake early warning system

hóng sè yù jǐng

红色预警

red alert

jǐng chá zài háo wú yù jǐng de qíng kuàng xia cháo rén qún kāi qiāng

警察在毫无预警的情况下朝人群开枪。

Police fired into the crowd without warning.

zuó yè bào yǔ zhī hòu zhè ge chéng shì fā chū le hóng shuǐ yù jǐng

昨夜暴雨之后，这个城市发出了洪水预警。

A flood alert has been issued in the city after last night's heavy rain.