Sometimes instead of saying, "I forgot to do the homework!" we say, "It totally slipped my mind!" Or instead of saying "I dropped her priceless teapot!" we say "The priceless teapot just slipped through my fingers!"
The difference in the second sentences is an emphasis on the lack of intent or responsibility. We are stressing that this was a totally unexpected event that did not involve any deliberate action on our part.
In Spanish we use the pronoun Se with certain verbs to convey this idea.
We conjugate them in the third person singular or plural - much like Gustar type verbs - since we aren't actually doing the action: Rather, it is something happening to us.
We add in an indirect object pronoun to indicate whose mind the idea slipped out of (or through whose fingers the item or items slipped).
| Se me olvidó | It slipped my mind (vs. I forgot) |
| se te perdió | It misplaced itself on you (vs. You lost it) |
| Se nos cayó | It slipped through our fingers (vs. We dropped it) |
The verbs are conjugated in the singular or the plural depending on what has slipped through our fingers or gotten lost on us:
| Se le quedaron las llaves en la casa. | The keys were left behind in the house (on him or on her) |
| Se les ocurrió estudiar para el examen. | It occurred to them to study for the exam. |
| Se me cayeron los platos. | The plates slipped through my fingers. |
| Se nos rompieron las cintas. | The tapes broke on us. |
| Se nos perdió el libro. | The book got lost on us. |
You can also add your redundant indirect object using the preposition a, for emphasis or clarification:
| A mi hermana se le quedaron las llaves en la casa. | My sister's keys were left behind in the house. |
| A los estudiantes se les occurió estudiar para el examen. | It occurred to the students to study for the exam. |
| A nosotros se nos perdió el libro. | Our book got lost (not yours..) |