This is the 261st most frequent Chinese word.
干
"干" can mean "dry," "do," or "work," depending on the context.
In this sentence, '干' means 'to do' or 'to perform a task', implying an action or work being carried out.
他正在干一份很重要的工作。
He is doing a very important task.
Here, '干' is used as an adjective meaning 'dry', describing the lack of moisture in the weather.
昨天的天气真干，几乎没下雨。
Yesterday's weather was really dry, as it hardly rained.
In this question, '干' means 'to do', commonly used in spoken language to inquire about someone's activity or actions.