Using definite and Indefinite articles, fill the blanks:
Indefinite: Un, una, unos, unas
Definite: la, el, los , las

Examples.
Using definite articles. Filling the blanks:

_ caja
_ Lapicero
_ museos
_ abuelo

Examples.
Using indefinite articles. Fill in the blanks:

_ tía
_ hermano
_ playas
_ zapato