- Los estudiantes
los libros después de la lección.(cerrar)

PLEASE HELP, i don’t know what to put in for the blank and it has to be a stem changing word.

Los estudiantes cierran los libros después de la lección

For this question, it will be important to use the words "mejor" (better), "lo mejor" (the best), and "lo peor" (the worst). while "mejor" is comparative (you are comparing one thing to something else), "lo mejor" and "lo peor" are superlative (there is nothing else better or worse than what these words are describing - there is no comparison).  you could say something like: la música rap es mejor que la música clásica - que es lo peor - pero la música rock es lo mejor de todas las formas de la música (rap music is better than classical music - which is the worst - but rock music is the best out of all the forms of music).

That is correct! good job!