"What are you doing?" is a common Engpsh phrase used to ask someone about their current activity or occupation. It is a way of inquiring about someone's current state or actions.
Example in Engpsh:
"What are you doing today?"
"What are you up to?"
Translation in Chinese:
"你今天在做什么？"
"你正在做什么？"
The origin of this phrase is not clear, but it has been in use in the Engpsh language for many centuries. It is a simple and direct way of asking someone about their current activity, and is commonly used in both casual and formal settings.