突然

当然 dāngrán HSK 3 #163

of course; naturally / certainly; without doubt

然后 ránhòu HSK 3 #145

then; after that

居然 jūrán HSK 5 #1,043

unexpectedly; to one's surprise / actually (expressing disbelief)

竟然 jìngrán HSK 4 #1,549

unexpectedly / to one's surprise / actually

忽然 hūrán HSK 4 #6,583

suddenly

突然间 tūránjiān

suddenly / all at once; in an instant

突发 tūfā HSK 6 #7,264

to break out suddenly / sudden (event) / unexpected

虽然 suīrán HSK 2 #629

although; even though

显然 xiǎnrán HSK 5 #876

obviously; evidently; clearly / it is apparent that

仍然 réngrán HSK 4 #1,027

still / as before / nevertheless