as you can; as much/as ... as you can
Deja tu cuarto tan impecable como puedas.
Leave your room as spotless as possible.
Jump as high as you can.
Lee tantos periódicos como puedas para mantenerte al día.
Read as many newspapers as you can to stay up to date.
Sé tan cortés como puedas cuando pides direcciones.
Be as polite as possible when asking for directions.
Lee tantos libros como puedas mientras seas estudiante.
Read as many books as you can while you are a student.