ni hao!

When you want to express “all of a sudden” or “suddenly”, there are two words that might come to mind: 突然 and 忽然. Both of these words can be used before verbs as an adverbial modifier. But are these two words the same? Can they replace each other without any conditions? Of course not! They share the same meaning but play different roles in the sentence.

忽然(hūrán) vs 突然(tūrán)

忽然(hūrán)
忽然 is an adverb which can only be an adverbial modifier in a sentence. Plus,
there should not be any adverb of degree before it.
For example,
I suddenly miss home very much.
⚫ 我忽然非常想家。(Wǒ hūrán fēicháng xiǎng jiā.) √
⚫ 我非常忽然想家。(Wǒ fēicháng hūrán xiǎng jiā.) X
I got up too early today, I suddenly got sleepy.
⚫ 今天起床太早，我忽然有点儿困了。(Jīntiān qǐchuáng tài zǎo, wǒ hūrán yǒudiǎnr kùnle.)
√
⚫ 今天起床太早，我有点儿忽然困了。(Jīntiān qǐchuáng tài zǎo, wǒ yǒudiǎnr hūrán kùnle.)
×
突然(tūrán)
突然 is an adjective which can be a predicate, an attributive, a complement, as
well as adverbial modifier. Moreover, the adverb of degree can modify the word.
For example,
⚫ 这个事情很突然。(Zhège shìqíng hěn tūrán.) This thing is very sudden.
-> As predicate
⚫ 这个突然的消息让人很意外。(Zhège tūrán de xiāoxī ràng rén hěn yìwài.)
This sudden news is very surprising.
-> As attributive
⚫ 这场雨下得很突然。（Zhè chǎng yǔ xià dé hěn tūrán.）This rain is very sudden.
->As complement
www.digmandarin.com
⚫ 我突然非常想家。（Wǒ tūrán fēicháng xiǎng jiā.）I suddenly miss home very much.
->Adverbial modifier
Now let’s do some practice to review. Please fill in the blanks with “忽然” or “突
然” to complete the sentences.
1. He suddenly ran in.
他______就跑进来了。
(Tā ______ jiù pǎo jìnlái le.)
2. He died too suddenly.
他去世得太_______了。
(Tā qùshì dé tài ______ nle.)
3. This sudden rain makes us a little bit surprising.
这________的雨让我们有点惊讶。
(Zhè_______de yǔ ràng wǒmen yǒudiǎn jīngyà.)
4. This news is very sudden.
这个消息非常_______。
(Zhège xiāoxī fēicháng ______.)
5. Suddenly, the office becomes very quiet.
_____，办公室变得很安静。
(_____, bàngōngshì biàn dé hěn ānjìng.)
6. It`s suddenly cold today.
今天_______冷起来了。
(Jīntiān ______ lěng qǐláile.)

Key:
1. 他突然/忽然就跑进来了。
2. 他去世得太突然了。
3. 这突然的雨让我们有点惊讶。
4. 这个消息非常突然。
5. 忽然/突然，办公室变得很安静。
6. 今天突然/忽然冷起来了。