Subject + 居然 + Verb Phrase
居然 (jūrán) expresses surprise that something unexpected has happened, similar to "actually" or "unexpectedly" in English. It conveys the speaker's disbelief or astonishment, and can be used for both positive and negative surprises.
他居然通过了那么难的考试!
Tā jūrán tōngguò le nàme nán de kǎoshì!
He actually passed such a difficult exam!
没想到这家小店的菜居然这么好吃。
Méi xiǎngdào zhè jiā xiǎo diàn de cài jūrán zhème hǎochī.
I didn't expect the food at this little restaurant to be so delicious.
她居然一个人跑完了全程马拉松。
Tā jūrán yī gè rén pǎo wán le quánchéng mǎlāsōng.
She actually ran an entire marathon by herself.