be surprised at /to
be surprised at somebody/something/doing something对某人的行为/某事/干谋事感到惊讶
I am surprised at you.我对你的行为跟到惊讶。
I was surprised at your tone.我对你的腔调吃惊不小。
I was surprised at seeing/to see him there.我真想不到在那里见到他。
be surprised to do something对干某事感到很惊讶
I'm surprised to hear you say that.我真想不到听到你说出这番话来。
可以看出，be surprised to do something跟be surprised at doing something意思一样。
surprise的用法
一\surprise是vt.&n.使吃惊；惊奇
1、in surpise惊奇地
2、by surpise出其不意地
3、to one's surpise使人吃惊的是
二＼surpised是adj.吃惊的
如：be surpised to do sth.
三＼surprising也是形容词，使人吃惊的（与surprised的区别是surprising对象是物体本身令人吃惊，是物体的属性）