without prior warning

• 没有事先警告

without prior warning的用法和样例：

例句

1. The bomb exploded without any prior warning.
   炸弹在没有任何事先警告的情况下爆炸了。
2. US ambassador Charles Reis said that while damage was "not extensive", the attack, which came without warning, was being treated seriously.
   美国大使查尔斯雷斯说，这次事件的危险虽然不大，但是没有事先警告的攻击必须得到严肃的对待。