No quiero un sueter de lana para el verano. prefiero un sueter de

Prefiero un sueter de lana para el invierno.

el verano is summer, and you do not want a woolen sweater in summerf, so the opposite of summer is winter, which is el invierno 

No quiero un sueter de lana para el verano prefiero un sueter de hilo                                                                                                            

Is this a spanish question that needs to be translated

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).