pensar VERB to think; to think about, to think over
Pensar is used as often in Spanish as to think is in English. For instance, if you want to ask someone’s opinion:
¿Piensas que vale la pena? Do you think it’s worth it?
(Remember, the -e in pensar changes to -ie in some cases)
To ask what someone thinks of someone or something, you put de after pensar:
¿Liliana, qué piensas de la propuesta? Liliana, what do you think of the suggestion?
In the last example, de is the Spanish equivalent of the English words of or about. But notice you use en in the structure pensar en alguien/algo to think of somebody/something:
¿En qué piensas? What are you thinking about?
If you’re thinking of doing something, you use the same preposition, en, followed by the infinitive:
Estábamos pensando en ir al cine esta tarde. ¿Nos quieres acompañar? We were thinking of going to the movies this afternoon. Do you want to come along?
Pensar can also be used with an object. For instance:
Piénsalo bien antes de responder. Think carefully before you answer.
No estoy muy convencida. Lo voy a pensar. I’m not totally convinced. I’ll think it over.
A couple of other useful phrases using this grammatical structure are:
pensándolo bien… thinking it over…, on reflection
¡Ni pensarlo! No way!
Pensándolo bien, he decidido no dimitir. On reflection, I’ve decided not to resign.
¿Casarme? ¡Ni pensarlo! Get married? No way!