"I am writing a book."
Translation:Yo escribo un libro.
There are to verbs in Spanish that mean to be. Ser & Estar. You use one or the other depending on the context of you sentence.
You use SER (Soy, Eres, Es, Somos, Son) when:
Describing/Identifying People or Things. Soy una persona/ I am a person. Soy Americana/ I am American
Describing a Person's Occupation. Ellos son profesores./They are teachers.
Talking About Relationships. Ella es mi madre./She is my mother.
Talking About Possession. Es libro de Maria. Son libros de Juan./ It is Maria's book. They are Juan's books.
Talking About the Time. Es mediodia./ It is noon.
You use ESTAR (Estoy, Estas, Esta, Estamos, Estan) when:
Talking about Temporary States. Ella esta enferma./ She is sick.
Talking about Present Continuous Estoy escribiendo un libro./ I am writing a book.
Talking about Location, NOT nationality. Donde estas?/ Where are you?
The translation they give is wrong. Also the question is misleading. Duolingo should review that problem because it is too advance to have it in that level.
For everyone asking why this isn't "Estoy escribiendo un libro": it can be! That is an acceptable translation of the sentence "I am writing a book." However, you need to understand a little about common usage, in addition to literal translation.
In English, the "-ing" form, like in "I am writing," is called the progressive tense. And we use it pretty exclusively to refer to actions that are currently going on, right now, not just in a vague habitual sense. Spanish...does it a little differently.
Spanish sometimes uses the simple present, the "I write" form, in the same way that English uses the progressive form. They're a lot more interchangable in Spanish! So, actually, if your English sentence says, "I am writing a book," then, semantically speaking, you could translate that either as, "Escribo un libro," or as "Estoy escribiendo un libro." Either one works! Likewise, "Escribo un libro," could be translated as either, "I write a book," or as "I am writing a book," and either one would be correct. One is more literal, while the other is a little closer to the actual intention of the sentence.
Tl;dr, semantics are important in translation, and sometimes the literal translation isn't the only acceptable or most natural one.
Hope this helps!
Since this is a progressive sentence (the action is in progress), you use the correct form of estar (in this case, estoy) and then add the verb with the correct ending (If the verb is an -ir verb, then you add -iendo in place of -ir). So since the verb is escribir, you change it to escribiendo. So all together, it is "Estoy escribiendo un libro."
"Soy" is only used when you want to mention a certain property of something. (Yo soy un hombre.) It is not used when you want to describe what someone is doing. Imagine the same sentence in present simple (I write). There is no form of "to be" present in such sentence and that's how it works in Spanish. What they really want to translate is "I write a book" in present simple, not in present continuous. It's a little confusing and I have no idea why they've decided to write it like that, but "I am (currently) writing a book" would translate differently.