When explaining policies and rules, like the etiquette at a local fitness center, you often need to state what "can" or "must" be done in a general sense. In Italian, you can do this by combining the passive si with modal verbs like dovere (must) and potere (can).
Rules for Singular Objects
When the object of the rule is singular (like a membership or a locker), use si + the singular modal verb (deve or può) + the infinitive of the action verb.
| To enter, the membership must be shown. | Per entrare, si deve mostrare l'abbonamento. |
| The membership can be paid at the checkout. | L'abbonamento si può pagare alla cassa. |
| Any free locker can be used. | Si può usare qualsiasi armadietto libero. |
Rules for Plural Objects
Because the object grammatically acts as the subject in a passive si sentence, the modal verb must agree with it. If the item being acted upon is plural (like backpacks or weights), use the plural form of the modal verb (devono or possono).
| Backpacks must be left in the locker room. | Gli zaini si devono lasciare nello spogliatoio. |
| Lockers must be closed with a padlock. | Gli armadietti si devono chiudere con un lucchetto. |
| The dumbbells must be put back on the shelf. | I manubri si devono rimettere sulla mensola. |
Negative Rules and Prohibitions
To explain what cannot or must not be done, place non directly before si. Remember that the modal verb still needs to agree with the number of the object!
| The towel is mandatory, it cannot be forgotten. | L'asciugamano è obbligatorio, non si può dimenticare. |
| The dumbbells cannot be left on the floor. | Non si possono lasciare i manubri sul pavimento. |