He went on and on about the benefits of spending an entire summer in this summer camp in the United States, stressing a little phrase that I didn't pay  too much attention to at the time: "You never know what the future holds."
Continúo hablando de los beneficios, de pasar un verano entero en un  campamento en Estados Unidos, recalcando una pequeña frase, a la que no presté mucha atención en el momento: "Nunca se sabe lo que depara el futuro."