We use the particle "と" in this case.
The structure of the phrase will be in this form:
[person]と[action] = did [action] together with [person]
For example:
- I went shopping with my mum. = watashi wa haha to isshoni kaimono shimashita. = 私は母と一緒に買い物しました。(isshoni = together with)
- I always quarrel with my younger brother. = itsumo otouto to kenka shimasu . = いつも弟とけんかします。(itsumo = always, kenka shimasu = quarrel)
