惊讶 + 于 + Cause
The verb 惊讶 (jīngyà) means 'to be surprised' or 'to be astonished.' It is often followed by 于 to introduce the cause of surprise, forming the pattern 惊讶于 + reason. This structure emphasizes what specifically triggered the feeling of astonishment.
我惊讶于他居然能说一口流利的日语。
Wǒ jīngyà yú tā jūrán néng shuō yì kǒu liúlì de Rìyǔ.
I was surprised that he could speak fluent Japanese.
大家都惊讶于这次考试的结果。
Dàjiā dōu jīngyà yú zhè cì kǎoshì de jiéguǒ.
Everyone was surprised by the results of this exam.
她惊讶于老朋友突然出现在门口。
Tā jīngyà yú lǎo péngyou tūrán chūxiàn zài ménkǒu.
She was surprised that an old friend suddenly appeared at the door.