Questions & Answers about Os cavalos não são tão lentos como os gatos.
How does the "as ... as" comparison work in this sentence?
Why is it lentos with an "s" instead of just lento?
In Portuguese, adjectives have to match the noun they are describing. Because os cavalos (the horses) is a masculine plural noun, the adjective describing them must also be masculine and plural, which gives us lentos.
Why does the sentence use são instead of estão for "are"?
Why do we need os before gatos? Can we just say "como gatos"?
When talking about things in general, English often drops the word "the", but Portuguese almost always keeps it. You need the definite article os (the) before plural nouns like gatos, even when making a general comparison at the end of a sentence.