あなたはその規則を守るべきだ。

you (referring to someone of equal or lower status); dear (what a wife calls a husband)

topic marker particle; indicates contrast with another option (stated or unstated); adds emphasis

that (something or someone distant from the speaker, close to the listener; actions of the listener, or ideas expressed or understood by the listener); the; um...; er...; uh...

rules; regulations; conventions

indicates direct object of action; indicates subject of causative expression; indicates an area traversed; indicates time (period) over which action takes place; indicates point of departure or separation of action; indicates object of desire, like, hate, etc.

to protect; to guard; to defend; to keep (i.e. a promise); to abide (by the rules); to observe; to obey; to follow

shall; should; must

be; is; indicates past or completed action; indicates light imperative