Questions & Answers about El niño tiene que cuidar al perro.
Why is there a "que" after "tiene"?
Why is "cuidar" not conjugated as "cuida" to match the boy?
Where does the word "al" come from?
al is a mandatory contraction. Whenever the preposition a is followed directly by the masculine word for "the", which is el, they merge into one word: al. You will never see a el written together; it always becomes al.
Why do we need the "a" (inside "al") before "perro"?
This is an example of the "personal a". In Spanish, when the object receiving the action of the verb is a specific person or a personalized animal (like a pet), you must put the word a before them. Since the boy is caring for a specific dog, we say cuidar a el perro, which contracts to cuidar al perro.