La abuela la arropó con la colcha y la miró con una ternura enorme.

Because each verb has its own direct object pronoun.

• la arropó = she tucked her in
• la miró = she looked at her

In Spanish, if two finite verbs both take the same object, you normally repeat the pronoun with each verb. Both las refer to the same feminine person, unless the wider context says otherwise.

In Spanish, unstressed object pronouns like la, lo, le, me, te usually go before a conjugated verb:

• la arropó
• la miró

That is the normal position. They can attach to the end only with certain forms, such as:

• an infinitive: arroparla
• a gerund: arropándola
• an affirmative command: arrópala

But with a normal past-tense verb like arropó or miró, the pronoun goes in front.

Here arropar means to tuck someone in or to cover someone up warmly with bedclothes.

It is more specific and warmer in tone than just cubrir (to cover). It often suggests care, protection, and affection, especially in scenes with a child, a sick person, or someone in bed.

So la arropó con la colcha is not just she covered her; it has the feeling of she tucked her in carefully.

Because the sentence presents two completed actions in a narrative:

• she tucked her in
• she looked at her

The preterite (arropó, miró) is the normal tense for events that happen and are seen as finished.

If you used the imperfect:

• la arropaba
• la miraba

it would sound more like background description, a repeated habit, or an ongoing scene rather than two clear completed actions.

Colcha usually means bedspread, coverlet, or sometimes quilt, depending on the exact situation.

The preposition con means with, and here it tells you what she used to tuck the person in:

• la arropó con la colcha = she tucked her in with the bedspread/quilt

Using en would change the meaning. For example, en la colcha would suggest something like in/on the bedspread, not the idea of using it to cover someone.

Because mirar and ver are not exactly the same.

• mirar = to look at
• ver = to see

Mirar suggests a deliberate act of directing your eyes toward someone or something.
Ver is more about perception: you see something.

In this sentence, the grandmother is not just noticing the person; she is looking at her in an intentional, affectionate way. That is why miró fits better.

Spanish often expresses manner with con + noun, and it can sound very natural, vivid, and slightly more literary.

• la miró con una ternura enorme = she looked at her with enormous tenderness
• la miró muy tiernamente = she looked at her very tenderly

Both are possible, but they are not identical in tone.

Con una ternura enorme focuses on the quality of the feeling.
Muy tiernamente focuses more directly on how the action was done.

The version in the sentence feels especially warm and expressive.

Yes, una enorme ternura would also be correct.

In Spanish, adjectives often come after the noun in the more neutral, usual order:

• una ternura enorme

Putting the adjective before the noun often adds a little more emphasis or subjectivity:

• una enorme ternura

So both work, but ternura enorme sounds very natural and straightforward here.

Because la abuela can mean the grandmother or simply Grandma/the grandma when the context already makes clear whose grandmother she is.

Spanish often uses the definite article with family roles in narration when the person is already known from context:

• La abuela entró
• El padre se sentó
• La madre sonrió

If it were important to specify ownership, you could say su abuela (his/her grandmother). But if the story already makes that clear, la abuela is enough and sounds natural.

They show both pronunciation and tense/person.

• arropó = he/she tucked in
• miró = he/she looked

The written accents show the stress falls on the last syllable:

• arropó
• miró

They also distinguish these forms from the present tense first person singular:

• arropo = I tuck in / I cover warmly
• miro = I look

So the accents are important: they help tell you that these are third-person singular preterite forms.