Rule reminder
Use 'è + adjective + infinitive' (impersonal infinitive) when NO specific subject is stated: 'È difficile capire questo testo.' Use 'è + adjective + che + subjunctive' when a specific subject IS present: 'È difficile che lui capisca.' The infinitive construction is more concise and preferred in formal/written Italian when the subject is truly unspecified. With a subject pronoun or noun, the 'che + subjunctive' construction is obligatory.
_____ imparare una lingua senza pratica costante. (general statement, no specific subject)