出其不意

The police surprised the thief into confessing.

其不意地使小偷招认了。

I was surprised by the abrupt change of subject.

其不意变换题目让我很吃惊。

Look, you whiney crybaby, we're not wasting the element of surprise to mollify your nyctophobia.

听着，你这个瞎抱怨爱哭鬼，我们可不会为了迁就你黑夜恐惧症而浪其不意这一要素。

This is a very quick and surprisingly effective way to limit your opponent's economy and is especially effective against the turtler because they honestly won't be expecting it.

这是个限制敌人经济非常迅速而又其不意有效方式，而在对抗龟派时尤其有效，因为它们通常不会想到。