我竟然忘记了他的生日。
wǒ jìngrán wàngjì le tāde shēngrì 。
I actually forgot his birthday.
她居然竟然在这里遇见了我。
tā jūrán jìngrán zài zhèlǐ yùjiàn le wǒ 。
She unexpectedly met me here.
你竟敢在课堂上睡觉！
nǐ jìnggǎn zài kètáng shàng shuìjiào ！
You actually dare to sleep in class!