by surprise

基本解释

He was rooted to the spot by surprise.
他惊讶得一动不动地站在原地。
They were constantly on the alert not to be taken by surprise.
他们一直处于常备不懈状态以防突然袭击。
《新英汉大辞典》
The Armies were constantly on the alert not to be taken by surprise.
部队一直处于警戒状态以防突然袭击。
《新英汉大辞典》

The flooding caught most people by surprise.
They can't imagine -they don't have the power of imagination to think what the next crisis will be like, so it catches them by surprise.
他们无法想象,他们根本想象不出,下次危机爆发是什么样,所以危机发生时他们措手不及
耶鲁公开课 - 金融市场课程节选
This was a tremendous embarrassment to the Bank of England and Mervyn King, who was a very good governor of the Bank of England; but this apparently took him by surprise.
这使英格兰银行及其行长金默文,陷入窘迫境地,虽然他曾是英格兰银行非常杰出的管理者,但这次挤兑显然出乎他的预料
耶鲁公开课 - 金融市场课程节选

The personal computer took America by surprise, and then by storm, in the late 1970s.
FORBES: 2002 hangs on these