一鼓作气 One drumbeat to boost morale
Explanation
一鼓作气，意思是第一次击鼓时士气振奋。比喻趁劲头大的时候鼓起干劲，一口气把工作做完。
„One drumbeat to boost morale“ literally means the first drumbeat that boosts morale. It describes the situation where you seize the opportunity to move forward with vigor and complete a task in one go.
Origin Story
春秋时期，齐国恃强凌弱攻打鲁国，鲁庄公率军迎敌。两军相遇，齐军擂起战鼓，而鲁军在曹刿的带领下没有擂鼓。齐军第三次擂鼓时士气已经低落，鲁军才第一次擂鼓。鲁军靠的就是一鼓作气的士气以少胜多，打败了齐军。
During the Spring and Autumn Period, the powerful state of Qi attacked the weak state of Lu. Duke Zhuang of Lu led his army to meet the enemy. When the two armies met, the Qi army beat the drums, but the Lu army did not beat the drums under the leadership of Cao Gui. Only when the Qi army beat the drums for the third time and their morale was already low, did the Lu army beat the drums for the first time. The Lu army defeated the Qi army by relying on their high morale and their ability to make a concerted effort.
Usage
这个成语主要用来形容一个人做事要抓住时机，鼓起勇气，一口气把事情做完。
This idiom is mainly used to describe that a person should seize the opportunity, summon up courage, and complete the task in one go.
Examples
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我们要抓住时机，一鼓作气，完成任务。
wǒ men yào zhuā zhù shí jī, yī gǔ zuò qì, wán chéng rèn wù.
We must seize the opportunity, make a concerted effort, and complete the task.
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他一口气写完这篇论文，真是令人佩服。
tā yī kǒu qì xiě wán zhè piān lùn wén, zhēn shì lìng rén pèi fú.
He finished writing this paper in one go, which is really admirable.
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在关键时刻，我们一定要一鼓作气，争取胜利。
zài guān jiàn shí kē, wǒ men yī dìng yào yī gǔ zuò qì, zhēng qǔ shèng lì.
At the critical moment, we must make a concerted effort to win.
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他们一鼓作气，终于完成了这项艰巨的任务。
tā men yī gǔ zuò qì, zhōng yú wán chéng le zhè xiàng jiān jù de rèn wù.
They made a concerted effort and finally completed this arduous task.
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在比赛中，我们必须一鼓作气，才能取得最后的胜利。
zài bǐ sài zhōng, wǒ men bì xū yī gǔ zuò qì, cái néng qǔ dé zuì zhōng de shèng lì.
In the game, we must make a concerted effort to win the final victory.