Well, make up your mind. Which do you want? This one or that one?

哎，拿定主意。你要哪一个？这个还是那个？

《牛津词典》

You must make up your mind.

你必须下定决心。

youdao

If you make up your mind to pursue your goal, you should begin to study hard.

如果你下定决心要追求你的目标，那么你就要开始努力学习了。

youdao

All right, I'm going to give you ten seconds fifteen seconds to make up your mind.

差不多打成平手,其他人现在不知道。

麻省理工公开课 - 热力学与动力学课程节选

Senator STEVENS: It may be that what we've done leaves an impression we've done something wrong, but you have to make up your mind you're doing something wrong, you have to have an intention to do something wrong to really be guilty of a crime.

NPR: Taped Phone Conversations Played At Stevens Trial

SARCs are mostly able to assist in the immediate aftermath of an assault and can store the forensic results until you make up your mind whether to report to the police or not.

BBC: Jimmy Savile: Help and support

That's how you make up your mind.

ECONOMIST: An Italian in Liverpool