忽然 和 突然
suddenly: 忽然 is only an adverb; 突然 is also an adjective
Structure
忽然／突然 动词 · 很／太 突然 · 突然（的） 名词
What it means
Both mean “suddenly” before a verb. 忽然 is only an adverb; 突然 is also an adjective, so it can take 很 or 太 and describe nouns.
How it is built
忽然／突然 + verb: 手机忽然响了 (the phone suddenly rang). 突然 as an adjective: 太突然了 (so sudden), 突然的消息 (the sudden news).
When to use it
忽然 is a little softer and more literary; 突然 stresses that it was abrupt and unexpected. Only 突然 can be the predicate or describe a noun (突然事件).
Watch out
✗ 太忽然了。 ✓ 太突然了。 ✗ 忽然的消息 ✓ 突然的消息. If in doubt, 突然 works in every slot.
Examples
我正在公司加班，手机忽然响了。
I was working late at the office when my phone suddenly rang.
爷爷走得太突然了，我们谁也没有准备。
Grandpa died so suddenly that none of us was prepared.
这个突然的消息让全家人都不知道说什么好。
The sudden news left the whole family lost for words.
Learn this in Lesson 44 · HSK 5–6: 白事与清明 (Funerals and remembering the dead)
A dialogue, a reading, word cards with audio and a drill that uses it, in Learn Chinese with Bao. The first lessons of every level are free.
Open the lesson →