To jump the gun is to do something too soon.

To jump the gun。 To jump就是“跳高”或“跳跃”的“跳”。

youdao

I did not want to jump the gun by saying the agreement would increase jobs for Americans.

我不想过早的说，这个协定将为美国增加就业机会。

youdao

To jump the gun means to start running before you hear the gun, to start running too early.

过早行动意味着在你听到枪前就开始跑了。跑得过早了。

youdao

That one also appeared to jump the gun.

WSJ: Moyes to Take Helm at Manchester United

But New York refused to jump the gun.

NEWYORKER: A Dirty Business

It creates an unfair, jump-the-gun, time-to-market advantage, by ignoring the rule of law standard of securing permission from property owners before use in the marketplace, a business practice that law-abiding competitors must respect.

FORBES: The Evidence Google's Systematic Theft is Anti-Competitive