Learn Spanish (Latin America): ¿Tú compras las flores?

The singular word for "flower" is flor. In Spanish, when a noun ends in a consonant (like the letter r), you make it plural by adding -es. That is why flor becomes flores.

How do I know to use las with flores?

Flor is a feminine noun, so you use the feminine plural word for "the", which is las. Even though flor doesn't end in -a, it is still feminine. Some noun genders just have to be memorized!

Why does the word tú have an accent mark over the 'u'?

The accent mark tells apart two words that sound exactly the same: tú means "you" (as the subject of the sentence), while tu without the accent means "your". Since the sentence means "Do you buy...", we need the accent mark.

Where is the word for "do" in this sentence?

Spanish doesn't use helper words like "do" or "does" to ask questions. You simply put question marks around the regular statement, so Tú compras (You buy) becomes ¿Tú compras? (Do you buy?). When speaking, you just raise the pitch of your voice at the end.