este libro (this book)
estos libros (these books)
esta pluma (this pen)
estas plumas (these pens)
ese libro (that book)
esos libros (those books)
esa pluma (that pen)
esas plumas (those pens)
aquel libro (that book over there)
aquellos libros (those books over there)
aquella pluma (that pen over there)
aquellas plumas (those pens over there)