Learn Hardcore Italian: Se il bibliotecario fosse assente, cercherei il libro da solo. - If the librarian were absent, I would look for the book by myself.

Fosse is the imperfetto congiuntivo (imperfect subjunctive) of essere. In Italian, we use the subjunctive mood in “if” clauses (protasis) when talking about hypothetical or contrary-to-fact situations. Here the speaker imagines the librarian being absent, so the imperfect subjunctive is required.

Why is cercherei used instead of a simple past or future tense?

Cercherei is the condizionale presente (present conditional) of cercare. In the main clause (apodosis) of a hypothetical sentence, Italian uses the conditional to say what one would do if the condition were met. It doesn’t express a real past action or a certain future event, but rather a potential action dependent on the hypothetical condition.

What is the general rule for combining se with the imperfect subjunctive and the conditional?

For present-time or future hypotheticals that are unlikely or unreal, Italian follows this pattern:

Protasis (if-clause): se
- imperfetto congiuntivo
Apodosis (main clause): condizionale presente
Examples:
• Se avessi tempo, verrei con te.
• Se fosse ricco, comprerei una villa.

Could I say Se il bibliotecario non c’era instead of Se il bibliotecario fosse assente?

No, because non c’era (imperfetto indicativo) treats the absence as a simple past fact. To express an unreal or hypothetical absence, you need se + imperfetto congiuntivo, e.g. Se il bibliotecario non ci fosse or the given version Se il bibliotecario fosse assente.

What’s the difference between assente and mancante?

Assente means “absent,” referring to a person or sometimes an expected presence (e.g. a student, an employee). Mancante means “missing” or “lacking” and is used more for objects or abstract things (e.g. a missing piece, a missing element). So for a person not being there, assente is the normal choice.

Why is it da solo at the end, and not just solo?

Solo by itself most often means “only.” Da solo means “alone” or “by oneself.” Saying cercherei il libro solo could be misinterpreted as “I would only look for the book.” Placing da solo clarifies that the speaker means “on my own, without help.”

Could we move da solo before the verb, like Da solo cercherei il libro?

While it’s technically possible, it feels stilted in everyday Italian. The most natural position for adverbial phrases like da solo is after the verb or at the end of the clause: cercherei il libro da solo.

Why is it il libro (definite article) instead of un libro (indefinite)?

Using il libro implies a specific, known book (perhaps one already mentioned or understood by speaker and listener). Un libro would mean “a book” in general, introducing something unspecified. Here the context suggests you already know which book you’re talking about.