what is it?
Spanish has two distinct constructions for describing ease or difficulty. In the first, an adjective such as fácil, difícil, imposible, duro, or complicado follows a named subject and is linked to an infinitive by de. The subject of the sentence is understood as the object of that infinitive: «Este libro es fácil de leer» (the book is what gets read). In the second construction the sentence is impersonal — it begins with es + adjective — and the infinitive follows directly, without de, with its own object expressed after it: «Es difícil comprender su conducta». Choosing the wrong pattern — or mixing elements of both — is a common source of error.
when to use it
Use adjective + de + infinitive when the grammatical subject of the sentence is also the understood object of the infinitive. The adjective agrees with that subject in gender and number. This pattern is common when the subject is a thing or concept: «Esa mancha es imposible de quitar» — the stain is what gets removed.
Use es + adjective + infinitive (no de) for impersonal statements about an action in general. There is no named subject; «es» is invariable and the adjective stays in the masculine singular. The object of the infinitive, if stated, appears after the infinitive itself: «Es difícil comprender su conducta».
The same adjectives work in both patterns. Fácil, difícil, imposible, duro, and complicado all appear in both constructions. The pattern is determined by sentence structure, not by the adjective chosen.
formation
The two patterns have different word orders and differ in the presence or absence of de.
| pattern | structure | example |
|---|---|---|
| subject pattern | subject + ser + adjective + de + infinitive | Este libro es fácil de leer. |
| impersonal pattern | es + adjective + infinitive (+ object) | Es difícil comprender su conducta. |
In the subject pattern, the adjective agrees with the subject: «Estas preguntas son difíciles de responder». In the impersonal pattern the adjective is always masculine singular regardless of any noun that follows.
examples in context
common pitfalls
Inserting de in the impersonal pattern. Learners often write «*es difícil de encontrar trabajo» by analogy with the subject pattern. Because there is no named subject that functions as the object of the infinitive, «de» has no role here. The correct form is «es difícil encontrar trabajo».
Omitting de in the subject pattern. The reverse error produces «*este libro es fácil leer». When the sentence subject is the understood object of the infinitive, «de» is obligatory. The correct form is «este libro es fácil de leer».
Adding a redundant object pronoun after the infinitive. Because the subject already fills the object role, adding a clitic pronoun is redundant and ungrammatical: «*su conducta es difícil de comprenderla». The subject «su conducta» is already the implicit object of «comprender». The correct form is simply «su conducta es difícil de comprender».