Before you try translating a sentence using "by," you need to ask yourself, "what does this word mean?" In many cases, if you can reword the sentence to express the same thought or relationship in different words, you are well on your way to figuring out what you want to say in Spanish.
Here are some of the most common meanings of "by" with examples of how the same thing can be said in Spanish. Keep in mind that in many cases the translations given are not the only ones possible.
To indicate the agent or cause: Usually, you can say that something was created or put in its present condition by someone or something using the preposition por. If the word or phrase (known as an object) following "by" answers the question "who or what did it?" then por is your likely choice. This is especially true when "by" follows a past participle.
- "Hamlet" was written by Shakespeare. "Hamlet" fue escrito por Shakespeare.
- The area affected by the sound is very large. La zona afectado por el sonido es muy grande.
- Ozone is a gas formed by the action of sunlight. El ozono es un gas que se forma por la acción de la luz solar.
However, in sentences in English that can be reworded to use the name of an author as a description, the preposition de is usually used in translation:
- "Volver" is a film by Almodovar. ("Volver" is an Almodovar film.) "Volver" es una película de Almodóvar.
- Where I can I buy books by Mark Twain in Spanish? (Where I can I buy Mark Twain books in Spanish?) ¿Dónde puedo comprar libros de Mark Twain en español?
- We are traveling by plane from New York to London. Viajamos en avión desde Nueva York a Londres. Viajamos por avión desde Nueva York a Londres.
- Traveling by car through Norway is easy and pleasant. Viajar en coche por Noruega es sencillo y agradable.
Indicating proximity: When "by" means "near" or "next to," cerca de or junta a can be used:
- There is a large park by the library. Hay un gran parque junto a la biblioteca.
- All the hotels can be found located by the beach. Todos los hoteles se encuentran ubicados cerca de la playa.
Untranslated "by" when using the Spanish present participle: Spanish often uses present participles (the verb form ending in -ando or -endo) in a way that doesn't have an exact English equivalent but is used to indicate the means by which a goal or state of being is accomplished. In such cases, the sentences can convey the meaning of the English "by." Examples:
- A fake doctor got rich by diagnosing nonexistent cancers. Un falso doctor se hizo rico diagnosticando cánceres inexistentes.
- By studying weekends, Susana will pass the test. Estudiando los fines de semana, Susana aprobará el examen.
In arithmetic: "To divide by" is dividir entre, while "to multiply by" is multiplicar por. When dimensions are given, por is used: tres metros por seis, three by six meters.
Meaning "per": Where "by" is the rough equivalent of "per," use por: Compramos los huevo por docenas, we buy eggs by the dozen (per dozen).
Idiomatic phrases: Numerous idiomatic phrases using "by" often can't be translated word for word. The concept may be expressed in some other way in Spanish other than directly translating "by." Some examples:
- I want to do it by myself. Quiero hacerlo sin ayuda. (The phrase is translated as the Spanish equivalent of "without help.")
- You could follow our trip almost day by day thanks to David's blog. Pudisteis seguir nuestro viaje casi día a día gracias al blog de David.
- By the way, the book has 100 pages. Por cierto, el libro tiene 100 páginas.
- We want to eat by candlelight. Querermos comer a las luz de las velas.
- Pablo introduced all the teachers to us one by one. Pablo nos presentó uno a uno todos los profesores.
- What do you mean by "difficult"? ¿Qué quieres decir con "dificil"?