When someone performs an action on or for themselves, you use the reflexive pronoun si (himself, herself, themselves). However, when you combine si with a direct object pronoun (lo, la, li, le) to say they do something with it or them, the si changes to se.
This creates the combined pronouns se lo, se la, se li, and se le.
| it for himself/herself/themselves (se la, se li, se le) | se lo |
Matching the Object
The second part of the combined pronoun (lo, la, li, le) must match the gender and number of the object being handled, taken, or worn.
For example, la felpa (the sweatshirt) is feminine singular, so we use se la. Il braccialetto (the bracelet) is masculine singular, so we use se lo.
If the objects are plural, use se li for masculine items (like i sandali) and se le for feminine items.
Combined Reflexives in the Past Tense
Because these phrases use reflexive verbs, they must take essere in the passato prossimo (past tense).
There is a strict rule when using a combined pronoun in the past tense: the ending of the past participle (like messo) MUST agree in gender and number with the direct object pronoun, not the subject.
- Il pigiama is masculine singular (lo), so the participle ends in -o: se lo è messo.
- Le pantofole is feminine plural (le), so the participle ends in -e: se le è messe.