The question caught her completely off-guard and she did not know how to reply.

这个问题令她猝不及防，不知道怎么回答。

《柯林斯英汉双解大词典》

Her betrayal took me completely off guard.

她的背叛让我完全措手不及。

youdao

A border guard grumbles that the only tourist in weeks has set off her tripwire.

一个边防人员抱怨说，几个星期只来了这么一位游客，还就触发了她负责的虚拟警戒线。

youdao

The teen says the outpouring of support caught her off guard.

CNN: STORY HIGHLIGHTS

But the digital age can still catch her off guard.

WSJ: Toni Morrison talks to Google about creativity

He was caught off guard, and tried to explain, then comfort her.

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