Here are the matches for the sentences:
- Mi sacapuntas está en mi mochila - My pencil sharpener is in my backpack.
- Los relojes están encima de la mesa. - The clocks are on top of the table.
- El estudiante está delante de la ventana. - The student is in front of the window.
(Note: I've corrected the spelling of "sharpener" in the response.)