Si buscas una novela de fantasía con un poco de misterio, te puedo prestar la que terminé ayer.

After si meaning if, Spanish normally uses the indicative, not the subjunctive, for real or possible conditions.

So:

• Si buscas... = correct
• Si busques... = incorrect here

A very common pattern is:

• Si + present indicative + present/future/ir a/periphrasis

For example:

• Si tienes tiempo, hablamos.
• Si vienes mañana, te lo doy.

In this sentence, Si buscas... means If you’re looking for... or If you want... depending on context.

Yes. In Spanish, the simple present often covers meanings that English expresses with either:

• you look for
• you’re looking for

So Si buscas una novela... can naturally mean:

• If you’re looking for a novel...
• If you want a novel...
• If you happen to be looking for a novel...

If you said Si estás buscando..., that would put more emphasis on the action being in progress right now. Both are possible, but Si buscas... is very natural and idiomatic.

Te is the indirect object pronoun, meaning to you.

So:

• puedo prestar = I can lend
• te puedo prestar = I can lend to you

Spanish often uses these short object pronouns where English uses a longer phrase.

Compare:

• Te doy el libro. = I give you the book.
• Te puedo prestar la novela. = I can lend you the novel.

Yes. Both are correct.

• Te puedo prestar la que terminé ayer.
• Puedo prestarte la que terminé ayer.

With a conjugated verb plus an infinitive, the pronoun can usually go:

• before the conjugated verb: te puedo prestar
• attached to the infinitive: puedo prestarte

Both are standard and natural.

If you also replace the direct object with a pronoun, you could get:

• Te la puedo prestar
• Puedo prestártela

Yes, dejar can also mean to lend in Spanish, especially in everyday speech.

• prestar = to lend
• dejar = literally to leave, but also commonly to lend

So these are both possible:

• Te puedo prestar la que terminé ayer.
• Te puedo dejar la que terminé ayer.

Prestar is very clear and explicit as to lend, so it is an excellent choice for learners.

Because de fantasía names the genre: fantasy.

• novela de fantasía = fantasy novel

By contrast, fantástica usually describes the novel as fantastic/amazing or sometimes fantastical, depending on context.

So:

• una novela de fantasía = a novel in the fantasy genre
• una novela fantástica = a fantastic novel / possibly a fantastical one

When talking about genres in Spanish, de + noun is very common:

• novela de misterio
• película de terror
• libro de ciencia ficción

This means the novel has some mystery in it.

The structure un poco de + noun means:

• a little bit of
• some

So:

• un poco de misterio = a bit of mystery / some mystery

The de is required after un poco when it is followed by a noun:

• un poco de agua
• un poco de tiempo
• un poco de humor
• un poco de misterio

This phrase softens the idea. It suggests the book is mainly fantasy, but with a touch of mystery.

La que terminé ayer means the one that I finished yesterday.

Spanish often avoids repeating a noun if it is already clear from context. Here, la stands for la novela.

So the full idea is:

• te puedo prestar la novela que terminé ayer

But Spanish often shortens that to:

• te puedo prestar la que terminé ayer

This is very common and natural.

Because la que means the one that and replaces the noun novela.

Compare:

• la novela que terminé ayer = the novel that I finished yesterday
• la que terminé ayer = the one that I finished yesterday

If you say only que terminé ayer, you are just saying that I finished yesterday, but you are missing the noun or substitute for it. La is what makes it into the one.

Because it refers back to novela, which is a feminine singular noun.

• la novela
• therefore la que terminé ayer

If the noun were masculine, you would use el:

• el libro que terminé ayer
• el que terminé ayer

So the article has to match the noun it replaces.

Terminé is the preterite because it refers to a completed action in the past:

• ayer = yesterday
• finishing the novel is a finished event

So:

• terminé ayer = I finished yesterday

The preterite is the normal tense for completed past actions tied to a specific time.

If you used the imperfect, terminaba, it would suggest an ongoing or repeated action, which does not fit here.

Yes, absolutely. That version is fully correct.

• te puedo prestar la novela que terminé ayer
• te puedo prestar la que terminé ayer

The second version is just more concise and more natural once novela has already been mentioned.

Spanish often prefers this kind of shortening when the noun is obvious from context.

Not completely. Spanish allows some flexibility.

These are all possible:

• Te puedo prestar la que terminé ayer.
• Puedo prestarte la que terminé ayer.
• La que terminé ayer te la puedo prestar. — more emphatic

The most neutral versions are the first two.

Spanish word order is often less rigid than English, especially with object pronouns, but not every rearrangement sounds equally natural in every context.