Mi hermana sabe envolver muy bien los libros y siempre hace un lazo perfecto.

Because after saber when it means to know how to do something, Spanish uses the infinitive.

• sabe envolver = she knows how to wrap
• not sabe envuelve

This is the same pattern as:

• Sé nadar = I know how to swim
• ¿Sabes cocinar? = Do you know how to cook?

So saber + infinitive is the key structure here.

Here saber + infinitive means to know how to do something, usually because it is a learned skill.

So:

• Mi hermana sabe envolver muy bien los libros = My sister knows how to wrap books very well

This is slightly different from poder + infinitive, which usually means to be able to in the sense of possibility or capability at that moment.

Compare:

• Sabe envolver regalos = She has the skill of gift-wrapping
• Puede envolverlos ahora = She is able to wrap them now

Because only the first verb, sabe, is conjugated. The second verb stays in the infinitive.

This is very common in Spanish when one verb depends on another:

• quiere comer
• puede venir
• sabe envolver

So mi hermana matches sabe, not envolver.

Muy bien modifies envolver. It tells you how well she wraps the books.

• bien = well
• muy bien = very well

So the idea is:

• sabe envolver muy bien los libros = she knows how to wrap books very well

It is acting as an adverb phrase, describing the action.

That position is very natural in Spanish. Adverbs that describe how an action is done often come after the verb or verb phrase.

So:

• sabe envolver muy bien los libros sounds natural

You could sometimes move things around, but this order is standard and clear.

Spanish word order is more flexible than English, but not completely free. In this sentence, the placement sounds smooth and idiomatic.

Spanish often uses the definite article where English might not, especially when referring to a specific set of things understood from context.

So los libros could mean:

• the books
• or, depending on context, simply books in a more natural English translation

Here it probably refers to the books she is wrapping, not just books in an abstract sense.

Compare:

• Envuelve libros = She wraps books / she wraps books in general
• Envuelve los libros = She wraps the books / the books in question

Because los libros is a thing, not a person.

The personal a is normally used with direct objects that are specific people (and sometimes pets or personified beings):

• Veo a mi hermana
• Conozco a tu profesor

But with things, you usually do not use it:

• Envuelve los libros
• Compra el regalo

So los libros appears without a.

Not exactly.

In this sentence, lazo means a bow, like the decorative bow made with ribbon when wrapping a present.

• lazo = bow
• nudo = knot

So if you are talking about gift wrapping, hacer un lazo is the natural expression for making that ribbon bow.

A nudo is more like a functional knot, not a decorative bow.

Because hacer un lazo is a normal Spanish expression meaning to make a bow.

Spanish often uses hacer in places where English might use make, do, or sometimes even another verb depending on context.

Here:

• hace un lazo perfecto = she makes a perfect bow

In real usage, this can imply the action of forming or tying the bow neatly.

Because the sentence is not talking about one specific, already identified bow. It is saying that she always makes a perfect bow.

So:

• un lazo perfecto = a perfect bow
• el lazo perfecto = the perfect bow / a specific bow already known

The indefinite article un is the natural choice here.

Because in Spanish, adjectives often come after the noun.

• un lazo perfecto
• una casa bonita
• un libro interesante

Putting the adjective before the noun is sometimes possible, but it often changes the tone or sounds more literary, emotional, or less neutral.

So un perfecto lazo is not the normal phrasing here. Un lazo perfecto is the standard, natural order.

Because mi here is a possessive adjective, meaning my, and it has no accent.

• mi hermana = my sister

Mí with an accent is a pronoun used after prepositions:

• para mí = for me
• sin mí = without me

So:

• mi hermana = correct
• mí hermana = incorrect

Siempre means always. It shows that this is a habitual action.

• y siempre hace un lazo perfecto = and she always makes a perfect bow

Its placement is natural because adverbs like siempre often come before the conjugated verb:

• Siempre hace un lazo perfecto
• Y siempre hace un lazo perfecto

That is a very common position in Spanish.

Not necessarily. In this sentence, the present tense describes a habitual or general fact.

• Mi hermana sabe...
• siempre hace...

This means something like:

• she is good at this
• she does this regularly
• this is her usual way of doing it

So Spanish present tense often covers what English expresses with the simple present for habits and general truths.

No. Envolver is a stem-changing verb.

Its stem changes from o to ue in many present-tense forms:

• envuelvo
• envuelves
• envuelve

But in this sentence it appears as the infinitive: envolver, so you do not see the stem change there.

That is why the sentence has:

• sabe envolver

not a changed form after sabe.

Yes. Envolver is a general verb meaning to wrap. The object tells you what is being wrapped.

So here, literally, she wraps books well. Depending on context, that may mean:

• she is good at gift-wrapping books
• she wraps books neatly, for presents or packaging

The sentence is specifically about los libros, so the skill is being applied to books in this case.