be careful
Quelque chose pourrait te tomber dessus, alors sois prudent.
Something might fall on you, so be careful.
But be careful.
Sois prudent en traversant la rue.
Be careful when crossing the street.
Sois prudent quant à ce que tu manges.
Be careful about what you eat.
Sois prudent quand tu traverses une route.
Be careful when crossing a road.