The sentence The work is to be done is interesting from several point of views. It is not a simple passive voice (the work is the goal of the action, but the executor of that action is not mentioned), but it expresses an obligation as well, the work must be done. This kind of construction is formed in Italian in a completely different way. The construction da + infinitivo is a passive form (although a very atypical one), has a subject that is not the subject of the finite verb and expresses obligation.
examples
Non ha ancora finito i lavori da fare.
He has not finished yet the works to be done.
Le fatture da pagare possono essere selezionate in base a diversi criteri.
The bills to be paid can be selected by different criteria.
I fattori da prendere in considerazione possono variare da azienda ad azienda.
The parameters to be taken into account can differ from one company to the other.
Ha indicato quali sono le misure da prendere per proteggere l'ambiente e la salute dei cittadini.
He explained the procedures to be performed to protect the environment and the health of the population.
