Answer:
- Conoces el sistema de transporte en Londres? Si sabes la dirección de tu amigo, tu teléfono inteligente/celular/móvil (smartphone) puede guiarte por el camino más rápido.
Explanation:
I chose "conoces" in the first phrase because "conocer" is used when talking about knowing an object, place or person while "sabes", chosen in the second phrase, is used means to know a fact or something.
I'd recommend revising the difference between saber and conocer.
Native speaker over here.
