Questions & Answers about Mi colchón es duro, pero me ayuda con el dolor de espalda.
Why is ser used in es duro instead of estar?
Why is the adjective duro masculine? Could I say dura?
Adjectives in Spanish must agree in gender and number with the nouns they modify. Colchón is masculine singular, so the adjective is duro (not dura). If you talked about a feminine noun (for example, almohada), you’d say almohada dura.
Why use pero instead of sino to connect the two clauses?
Could I replace pero with sin embargo?