Nov 04, 2020 - 04:27 PM
Put another way... if the thing you're talking about ends with "a" use an "a". Cerveza - buena
If the thing you are describing ends with "o" then "o". Libro - bueno
And add an "s" if you're talking about more than one thing. Cervezas - buenas, Libros -buenos. "a & o" match "a & o" and "s" matches "s".
Las cervezas son muy buenas. La cerveza es muy buena. Los libros son muy buenos. El libro es muy bueno.
After a lot of practice you will get a feel for them and it will become more natural and intuitive. In the meantime, it helps to remember that you will still be understood. Just like English speakers understand new speaker even when their grammar isn't yet prefect.