一口气 + Verb
一口气 (yīkǒuqì) is an adverbial expression meaning "in one breath," "at one go," or "without stopping." It emphasizes that an action is completed continuously without any break. It is placed before the verb it modifies, such as 一口气跑完 (run the whole way without stopping).
他一口气把这本小说读完了。
tā yī kǒuqì bǎ zhè běn xiǎoshuō dú wán le.
He read the entire novel in one breath.
她一口气跑上了六楼,气喘吁吁的。
tā yī kǒuqì pǎo shàng le liù lóu, qìchuǎnxūxū de.
She ran up six floors in one breath, panting heavily.
我一口气喝完了那杯冰水。
wǒ yī kǒuqì hē wán le nà bēi bīngshuǐ.
I drank the entire glass of ice water in one gulp.