Saber or Conocer?

Both verbs mean to know, but they are not interchangeable.

• saber is for facts and information, usually followed by a clause with qué, dónde, cuándo, si or que: No sé dónde está (I don't know where it is).
• saber + infinitive means know how to: Sabe nadar (she can swim).
• conocer is for people, places and things you are familiar with: Conozco a tu hermano (I know your brother), ¿Conoces Sevilla? (Have you been to Seville?).

Put the personal a before people: conocer a Lucía.

Present forms: sé, sabes, sabe, sabemos and conozco, conoces, conoce, conocemos. Watch the irregular yo forms: sé (with an accent) and conozco.