Learn Spanish (Latin America): Has puesto la taza sucia en la mesa.

Puesto is the irregular past participle of the verb poner (to put). While most -er verbs just add -ido in this tense (like comido), poner is an exception. Whenever you want to say "have put," you must use puesto.

Why do we use "has" for "have" instead of a form of "tener"?

In Spanish, there are two verbs for "to have." You use tener when you possess something (like tienes una taza, meaning "you have a cup"). But when "have" is a helper verb used to say what you have done, you must use the verb haber. Has is the "you" (tú) form of haber.

I thought "en" meant "in". Why does it mean "on" the table here?

The preposition en is very flexible and can translate to "in," "on," or "at" depending on the context. Since you usually place a cup on a table rather than inside it, en la mesa naturally translates to "on the table."

Why does "sucia" (dirty) come after "taza" (cup)?

In Spanish, descriptive adjectives like sucia usually come right after the noun they describe. It also ends in "-a" to match the feminine gender of taza.