Can you explain this sentence structure-Have you finished reading the book?

Question

¿Has terminado de leer el libro? Why wouldn't you use-¿Has terminado leyendo el libro? I guess you can't use the gerund following the particple? Also, what is the purpose of the "de" in this sentence? Why not just the infinitive leer? I am trying to figure this out because in English we sometimes use phrases like, Have you finished painting the garage? Have you finished eating dinner? etc.

Gracias como siempre

Answer 1

I'm no grammar expert, but I think this is a case of the infinitive being used as a subject or the object of a preposition. In English, when a verb is used as a verbal noun, an –ing word is used. For example , "I like singing," "Diving is fun," or, "Before eating, I washed the dishes." If you translated these directly into Spanish, you may be tempted to use the present participle (such as cantando, buceando, comiendo). This would be incorrect. you have to use the infinitive instead. In English we say "I am going fishing" but "fishing" is not the gerund form (at least in my mind), it is being used as a noun (an object). In Spanish I would say "Voy a pescar", using the infinitive.

Answer 2

Jack's answer is correct about using the infinitive form instead of the "gerund" when the verb is an object of a verb and when it is a subject of a sentence. The use of a verb as a noun in Spanish is accomplished by using the infinitive form and not the "-ing" or gerundio form of the Spanish verb: -ando, -iendo

Another part of your question deals with using a preposition to link the main verb with the infinitive. You need to learn which verbs need a preposition when used with an infinitive. We learn Voy a easily because it literally translates to I'm going to, but others are less intuitive. I think this is covered pretty well in the grammar section on this website.