In English, "去吧" can be translated to "go ahead" or "go for it." It is often used as encouragement or to give permission to do something.

One possible origin of this phrase is the Chinese phrase "去吧，勇敢地去" (qù ba, yǒnggǎn de qù), which means "go ahead, go bravely." This phrase was likely shortened to "去吧" over time.

Here are some examples of how "go ahead" or "go for it" can be used in English:

"Are you ready to give your presentation? Go ahead and start whenever you're ready."

"I know you're hesitant to try bungee jumping, but trust me, it's a lot of fun. Go for it!"

"I know you have a lot of work to do, but don't let that stop you from taking a break and going for a walk. Go ahead and take some time for yourself."