Here's how it breaks down:
* Ecris: This means "write" in French.
* Les jours: This means "the days."
* Ou: This means "where" or "when" in this context.
* Tu vas a: This means "you go to"
Here are some possible completions and their meanings:
* Ecris les jours où tu vas à l'école: Write the days when you go to school.
* Ecris les jours où tu vas au cinéma: Write the days when you go to the cinema.
* Ecris les jours où tu vas à la plage: Write the days when you go to the beach.
* Ecris les jours où tu vas au restaurant: Write the days when you go to the restaurant.
In short, "ecris les jours ou tu vas a" means "Write the days when you go to..."