Comparamos la calificación de dificultad con la calificación del terreno.

Spanish often leaves out subject pronouns when they are not needed, because the verb ending already shows who is doing the action.

• comparamos = we compare
• nosotros comparamos = we compare too, but with extra emphasis or contrast

So in this sentence, nosotros is simply understood.

Comparamos can be:

• present tense: we compare
• preterite: we compared

For -ar verbs, the nosotros form looks the same in both tenses. So only the context tells you which meaning is intended.

Here, if the English meaning shown to the learner is something like we compare, then it is being understood as the present tense.

That is just how regular -ar verbs work in Spanish.

For comparar:

• Present: nosotros comparamos
• Preterite: nosotros comparamos

This happens with many regular -ar verbs:

• hablamos
• estudiamos
• trabajamos

So you always need context to know whether it means we speak / compare / study or we spoke / compared / studied.

Because calificación is a feminine singular noun, so it takes la.

• la calificación de dificultad
• la calificación del terreno

Spanish usually uses articles more often than English does. In English you might sometimes say difficulty rating or terrain rating without repeating the, but Spanish normally keeps the article with each noun phrase.

Here calificación means something like:

• rating
• score
• assessment
• sometimes grade, depending on context

In this sentence, calificación is best understood as rating.

So:

• calificación de dificultad = difficulty rating
• calificación del terreno = terrain rating

Both are built with de, but they work slightly differently.

1. calificación de dificultad

This means difficulty rating.
Here, dificultad is used more like a category or type, so there is no article.

• de dificultad = of difficulty / difficulty

2. calificación del terreno

Here, del is a contraction of de + el.

• de + el = del

So:

• del terreno = of the terrain

This happens because terreno is being treated as a specific noun with the article el.

Because in Spanish, de + el almost always contracts to del.

• de el terreno ❌
• del terreno ✅

This is a standard grammar rule.

The only common exception is when el is part of a proper name, for example:

• de El Escorial

But with ordinary nouns like terreno, you must use del.

Because in phrases like this, Spanish often uses noun + de + noun to show type or category.

So calificación de dificultad means:

• rating of difficulty
• more naturally, difficulty rating

Other similar examples:

• nivel de agua = water level
• centro de salud = health centre
• mapa de carreteras = road map

In these structures, the second noun often appears without an article.

Because Spanish commonly says comparar algo con algo:

• Comparar X con Y = to compare X with Y

So:

• Comparamos la calificación de dificultad con la calificación del terreno.
• We compare the difficulty rating with the terrain rating.

You may also sometimes see comparar X y Y in Spanish, but comparar X con Y is very standard and very clear.

Yes, sometimes Spanish allows both patterns:

• comparar X con Y
• comparar X y Y

But comparar X con Y makes the relationship especially explicit, and it matches English compare X with Y very neatly.

In a sentence like this, con sounds very natural.

They both modify calificación.

So the sentence has two noun phrases:

1. la calificación de dificultad
2. la calificación del terreno

They tell us what kind of rating we are talking about.

You can think of the structure as:

• We compare [the difficulty rating] with [the terrain rating].

Yes. Spanish often allows that.

A shorter version would be:

• Comparamos la calificación de dificultad con la del terreno.

Here la stands in for la calificación.

That version is perfectly natural if the noun has already been mentioned and repeating it feels unnecessary.

The basic structure is:

• Comparamos = verb
• la calificación de dificultad = direct object
• con la calificación del terreno = comparison phrase

Spanish word order is fairly flexible, but this order is neutral and natural.

You could rearrange it in some contexts, but the original sentence is straightforward and standard.

No. The order matters.

• calificación de dificultad = difficulty rating
• dificultad de calificación would mean something more like difficulty of grading/rating, which is a completely different idea

So the noun after de tells you what kind of rating it is.

Terreno literally means:

• terrain
• ground
• land

In this sentence, calificación del terreno is best understood as terrain rating.

So it is not just the physical ground by itself, but the rating related to the terrain.

Because nouns ending in -ción are generally feminine in Spanish.

So:

• la calificación
• una calificación
• esta calificación

Other examples:

• la información
• la estación
• la comparación

The accent mark shows where the stress goes:

• ca-li-fi-ca-CIÓN

Without the accent, the word would not follow the correct written stress pattern.

Many Spanish nouns ending in -ción have this written accent:

• información
• comparación
• situación
• calificación

Yes. Calificación is a flexible word.

Depending on the context, it can mean:

• grade in school
• rating
• score
• mark
• evaluation

In this sentence, rating is the most natural meaning.

Because the sentence is talking about one difficulty rating and one terrain rating as concepts or single values.

So singular makes sense:

• la calificación de dificultad
• la calificación del terreno

If you were talking about several ratings, then you would use the plural:

• las calificaciones de dificultad
• las calificaciones del terreno

Possibly, depending on the context.

• calificación = rating / grade / evaluation
• puntuación = score / points
• valoración = evaluation / assessment

They are related, but not always interchangeable.
Calificación suggests a formal rating or assigned level, which fits this sentence well.

Yes, it is natural and grammatically correct in Spanish from Spain.

It sounds fairly neutral and could appear in a technical, instructional, or descriptive context. If the style needed to be slightly more concise, a Spaniard might also say:

• Comparamos la calificación de dificultad con la del terreno.

But the full version you were given is perfectly normal.