Find a photo from the past week where your child was doing something — not posing.
Show it and ask one open question: 'what were we doing here?' Then stay quiet.
Whatever comes back, expand it by one step. If they say 'water', you say 'yes, water — we were washing the car and you got wet.' Do not correct grammar; just hand back a slightly fuller version and let them take it or leave it.
Talking about a shared past event is the bridge from labelling what is present to narrating what is absent. Expanding a one-word answer models the next rung of grammar without ever telling the child they were wrong.