Learn Polish: Widać, że zdrowie dziadka się pogorszyło. - You can see that grandpa's health has worsened.

It is built from gorszy, which is the comparative form of zły (bad). By adding the prefix po- and a verb suffix, Polish creates the perfective verb pogorszyć (to make worse). The neuter past tense form here is pogorszyło to match the neuter noun zdrowie.

Why do we need the reflexive pronoun się here?

Without się, the verb pogorszyć means to make something else worse. Adding się makes it intransitive, showing a spontaneous change of state. So pogorszyło się means the health deteriorated on its own, rather than someone actively worsening it.

Why doesn't the Polish sentence say możesz zobaczyć for "You can see"?

When "you can see" means "it is apparent" or "one can tell" rather than the physical ability of a specific person, Polish uses the impersonal word widać. Using możesz zobaczyć here would sound awkwardly literal, as if you were telling someone they have the physical ability to look at a medical chart.

Why is się placed before the verb instead of at the end of the sentence?

While zdrowie dziadka pogorszyło się is grammatically acceptable, Polish generally avoids putting short, unstressed pronouns like się at the very end of a clause or sentence if there is a natural place for them earlier. Tucking it just before the verb creates a much more natural rhythm.