居然
Unexpectedly; to one's surprise
HSK 5HSK 3.0 · 5
S + 居然 + V/Adj
居然 expresses surprise that the outcome is contrary to what the speaker expected: 这么简单的题，你居然做错了！. The surprise can be positive (他学了三个月，居然能用汉语聊天了) or negative. It is synonymous with 竟然, goes after the subject and before the verb, and is the opposite of 果然. In listening, 居然 signals the speaker's surprise.
HSK 5 listening (surprise) and gap fills.
Examples
他学了三个月，居然能用汉语聊天了。
After just three months, he can actually chat in Chinese.
这么简单的题，你居然做错了！
You got such an easy question wrong!
外面下着大雪，他居然穿着短裤。
It's snowing heavily, and he's wearing shorts!
我没想到，他居然是老板的儿子。
I had no idea he was the boss's son.
Exercises
1.这么重要的会，他 忘了参加。
2.我以为这次考试很难，没想到 这么简单。
3.“他居然考了第一名”说明说话人：
4.我早就知道他会成功，他 成功了。