surprised可以视为形容词 也可以当做过去式或过去分词
当形容词使用时，一般是修饰人be surprised to do sth/be surprised at sth
I am very surprised at this news.
He was so surprised to hear this surprising news.
也可当动词过去式使用
What he said surprised me a lot yesterday.
surprised是形容词，多以人做主语，意思是对…感到吃惊。
固定搭配一般使用是be surprised at，意思是对…感到吃惊。
