正在
zhèngzài · HSK 1
be in process
⏳ 正 = right now + 在 = at/located → right now at (doing it)
正 marks the present moment and 在 means located at; together they form the progressive aspect marker, like English -ing. 我正在吃饭 = I am eating right now.
正 — one 一 + stop 止
Originally an ideograph showing a foot (止) advancing toward a target line (一), meaning 'to march straight toward' a city or goal. From this came the senses 'upright,' 'correct,' and 'proper.' The military sense survives in 征 (to campaign), which took over the original 'march' meaning.
在 — earth 土 + phonetic 才
Originally a phono-semantic compound: 土 (earth) gives the meaning of a place or location, while 才 supplies the sound. It came to mean 'to be present/located at,' and now also serves as a grammatical marker for ongoing actions, like 'in the middle of doing.'