突然 + Verb Phrase
突然 (tūrán) is an adverb meaning "suddenly" or "all of a sudden," used to describe an action or event that happens unexpectedly and without warning. It is placed before the verb or at the beginning of a clause.
我正在看书,突然听到外面一声巨响。
wǒ zhèngzài kàn shū, tūrán tīngdào wàimiàn yì shēng jùxiǎng.
I was reading when I suddenly heard a loud bang outside.
天气本来很好,突然就下起了大雨。
tiānqì běnlái hěn hǎo, tūrán jiù xià qǐ le dà yǔ.
The weather was originally nice, then it suddenly started pouring rain.
他突然站起来,把所有人都吓了一跳。
tā tūrán zhàn qǐlái, bǎ suǒyǒu rén dōu xià le yí tiào.
He suddenly stood up and startled everyone.