Breakdown of Oni nie powinni wyrzucać plastiku do rzeki.
nie
no / not
oni
they (masculine personal)
rzeka
river
do
to
Questions & Answers about Oni nie powinni wyrzucać plastiku do rzeki.
Why do we use powinni here instead of powinny?
Powinni is the masculine personal plural form of 'should.' It matches the pronoun oni (they), which is used for groups that include at least one man. If the group was entirely female, we would use one and the verb would change to powinny.
Why is the word for plastic spelled plastiku here instead of plastik?
Normally, the direct object of throwing is in the accusative case, which for this word is just plastik. However, because this sentence is negative (nie powinni wyrzucać), the object changes to the genitive case (plastiku). This rule is called the genitive of negation.
Could I use the perfective verb wyrzucić instead of wyrzucać here?
You could, but it changes the meaning slightly. The imperfective verb wyrzucać is used here to describe a general rule or repeated habit: they should not throw plastic into the river in general. Using the perfective wyrzucić would refer to a single, specific instance of throwing a piece of plastic.
Why does rzeka (river) change to rzeki in this sentence?