Then without warning, the troops opened fire on the crowd.

接着，在没有警告的情况下，军队向人群开了火。

Without warning, Bardo smacked his fist into his open hand.

毫无预警地，巴多用拳头啪地猛击了他张开的手。

You stopped without warning!

你没有提醒一下就停车！

Without warning, the earth began to shake.

没有任何预兆，大地开始震动。

The soldiers opened fire without warning.

士兵们未发警告就开了火。