Learn German: Man soll bitte keinen Müll auf der Straße werfen! - One should please not throw garbage on the street!

Man is an impersonal pronoun that means "one," "you" (in general), or "people." Even though it refers to people in general, it is always treated grammatically as a third-person singular subject (just like er, sie, or es). That is why the modal verb sollen (should) takes the third-person singular form soll.

Why do we use keinen here instead of nicht to say "not"?

When you negate a noun that has no article or an indefinite article, German uses a form of kein instead of nicht. Because Müll (garbage) is a masculine noun acting as the direct object of the sentence, it must take the Accusative case ending. Therefore, it becomes keinen Müll (literally: "no garbage").

Why is it auf der Straße (Dative) if throwing is an action?

auf is a two-way preposition. When paired with the Dative case (like the feminine der Straße), it describes a fixed location, answering "where?" (where is the action happening?). It means "while on the street." If it used the Accusative case (auf die Straße), it would specifically emphasize the motion of the trash traveling onto the street from somewhere else.

Why does the verb werfen (to throw) appear at the very end of the sentence?