Learn Spanish (Latin America): La puerta de la tienda está cerrada.

In this sentence, being closed is a physical state or condition of the door. Because it can change (the door can be opened later), we use está (from the verb estar). We use ser for permanent traits and identities, so saying es cerrada would sound strange, almost like the door was built shut forever!

Why does it say la puerta de la tienda instead of something like "la tienda's puerta"?

Spanish doesn't use an apostrophe 's' to show ownership. To say "the store's door," you have to flip the phrase around and use de (of), literally saying "the door of the store" (la puerta de la tienda).

Why does the word for closed (cerrada) end in an -a?

Because it describes la puerta (the door), which is a feminine noun. In Spanish, adjectives must match the gender of the noun they describe. If we were talking about a masculine word being closed, like el libro (the book), we would change the ending and say está cerrado.

Since there are two feminine nouns in this sentence (puerta and tienda), how do we know which one cerrada is describing?