Comparing "turan" and "huran"

Both 突然 (tūrán) and 忽然 (hūrán) express the something happens in a very short time or is unexpected. Both can be translated as "suddenly." However, 突然 is a bit harsher in tone while 忽然 is a bit softer (you might say 突然 is more 突然 than 忽然), and only 突然 can be used as an adjective meaning "sudden."

Both 突然 and 忽然 can be used as Adverbs

突然 and 忽然 both can put in the sentence as adverbs. Just make sure to put them before the verb or adjective they modify!

Before a Verb

突然／忽然 + Verb

Examples

• 睡觉 的 时候，我 的 电话 突然 响了。Shuìjiào de shíhou, wǒ de diànhuà tūrán xiǎng le.
• 睡觉 的 时候，我 的 电话 忽然 响了。Shuìjiào de shíhou, wǒ de diànhuà hūrán xiǎng le.While I was sleeping, my phone suddenly started to ring.
• 他 说着 说着 突然 不 说 了。Tā shuōzhe shuōzhe tūrán bù shuō le.
• 他 说着 说着 忽然 不 说 了。Tā shuōzhe shuōzhe hūrán bù shuō le.He was talking and talking, and suddenly stopped.

Before an Adjective

突然／忽然 + Adj.

Examples

• 天 突然 暗 了。Tiān tūrán àn le.
• 天 忽然 暗 了。Tiān hūrán àn le.The sky suddenly got dark.
• 灯 突然 不 亮 了。Dēng tūrán bù liàng le.
• 灯 忽然 不 亮 了。Dēng hūrán bù liàng le.The lights suddenly went out.

At the Beginning of a Sentence

You can place 突然 and 忽然 at the beginning of a sentence, just make sure to add a comma after it!

Structure

突然／忽然，⋯⋯

Examples

• 突然，他 进来 了。Túrán, tā jìnlái le.
• 忽然，他 进来 了。Hūrán, tā jìnlái le.Suddenly, he entered.

突然 can be used as an Adjective

突然 can be used as an adjective (directly modifying nouns), while 忽然 cannot.

Structure as an Adjective

突然 + (的) + Noun

Examples

• 这 是 一 场 突然 事故，我们 都 没 想到。Zhè shì yī chǎng tūrán shìgù, wǒmen dōu méi xiǎngdào.This was a sudden accident. None of us thought it could happen.
• 你 知道 怎么 处理 这 种 突然 的 情况 吗？Nǐ zhīdào zěnme chǔlǐ zhè zhǒng tūrán de qíngkuàng ma?Do you know how to handle this kind of sudden situation?

突然 can be used as a complement

突然 as an adjective can also be used as a complement (called 补语 in Chinese). 忽然 cannot be used as a complement.

Structure for verb and complement

Subj. + Verb + 得 + 突然

Examples

• 事情 发生 得 太 突然，我们 不 知道 怎么 办。Shìqing fāshēng de tài tūrán, wǒmen bù zhīdào zěnme bàn.Things happened so suddenly, we didn't know what to do.
• 这 场 雨 下 得 太 突然，都 淋湿 了。Zhè chǎng yǔ xià de tài tūrán, dōu lín shī le.This rain fell so suddenly, everything got soaked.

突然 can be used as the predicate

Just like other adjectives, 突然 can be used as the predicate of a sentence. It is usually added with a modifier like 很, 非常, 不 etc. It can also end with complements like 得很, 得多, 极了, etc.

Structure with modifier + 突然

Subj. + Modifier + 突然

Examples

• 这 个 决定 太 突然 了。Zhège juédìng tài tūrán le.This decision was too sudden.
• 对 她 来说，这 次 升职 其实 不 突然。Duì tā lái shuō, zhè cì shēng zhí qíshí bù tūrán.To her, this promotion wasn't actually surprising.

Structure with 突然 + modifier

Subj. + 突然 + Modifier

Examples

• 她 离开 上海 突然 得 很。Tā líkāi Shànghǎi tūrán de hěn.Her leaving Shanghai was really sudden.
• 这 次 生病 比 上 次 突然 得 多。Zhè cì shēngbìng bǐ shàng cì tūrán de duō.Getting sick this time was much more sudden than the last time.

Example of right and wrong sentences

• 这 个 决定 很 忽然。
• 这 个 决定 很 突然。 突然 can be a predicate, while 忽然 cannot.Zhège juédìng hěn tūrán.This decision is very sudden.
• 一切 发生 得 太 忽然。
• 一切 发生 得 太 突然。 突然 can be a complement, but 忽然 cannot.Yīqiè fāshēng de tài tūrán.Everything happened too suddenly.

Example Dialog

• A: 我 正在 睡觉，忽然 电话 响 了 ，是 Amy 打 来 的。Wǒ zhèngzài shuìjiào, hūrán diànhuà xiǎng le, shì Amy dǎ lái de.I was sleeping, when suddenly the phone rang. It was Amy.
• B: 她 说 什么 ？Tā shuō shénme?What did she say?
• A: 她 结婚 了 。Tā jiéhūn le.She got married.
• B: 啊，这 个 消息 太 突然 了。Zhège xiāoxī tài tūrán le.Oh, this news is really sudden.

Sources and further reading

Books

• 现代汉语八百词（增订本） (pp. 540) [ →buy]

• 现代汉语虚词例释 (pp. 247) 卓越汉语－公司实战篇 →buy

• Integrated Chinese: Level 2, Part 2 (pp. 231-2) Anything Goes (无所不谈) →buy

• Chinese Grammar - Broken down into 100 items - Basic and Intermediate Levels (汉语语法百项讲练 - 初中级) (pp. 113) Anything Goes (无所不谈) →buy

• HSK Standard Course 5上 (pp. 59) Anything Goes (无所不谈) →buy

Dictionaries

• 现代汉语词典（第5版） (忽然p.574 突然p.1378) →buy

:INVALID"INVALID" is not in the list (HSK0, HSK1, HSK2, HSK3, HSK4, HSK5, HSK6) of allowed values for the "HSK" property.