In Spanish, many verbs must be followed by a preposition, which may or may not correspond to the proposition (if any) used in English. The following is a list of some Spanish verbs which require prepositions con, en and por.
• Some can be followed by an infinitive or by a noun:
|Amenazar con to threaten to|
|Soñar con to dream about|
|Consentir en to agree to|
|Consistir en to consist of|
|Insistir en to insist|
|Interesarse en to be interested in|
|Pensar en to think about|
|Perseverar en to persevere in|
|Persistir en to persist|
|Quedar en to agree to|
|Empezar por to begin by/with|
|Luchar por to struggle, fight to|
Estoy pensando en volver a España (I am thinking about going back to Madrid).
Siempre he soñado con ganar la lotería (I have always dreamed of winning the lottery).
Me mostró la casa, empezando por la cocina (She showed me the house, starting with the kitchen).
• Other can be followed by a noun:
|Casarse con to get married to|
|Comparar con to compare with|
|Contar con to rely on|
|Encontrarse con to meet (by chance)|
|Enfadarse con to get annoyed with|
|Estar de acuerdo con to agree with|
|Hablar con to talk to|
|Entrar en to enter|
|Interesarse por to ask about, to be interested in|
|Preocuparse por/de to worry about|
Me enfadé con mi padre (I got annoyed with the official).
Entramos en el museo (We entered the Museum).
Se preocupa por su familia (He’s worried about his exams).
Remember that it is important you memorize these verbs along with the prepositions con, en and por, but take into account that these prepositions can be used in different situations.
On the other hand, if you want to learn more about Spanish prepositions you can ask for an online Spanish tutorship.