Learn Hardcore Portuguese (Portugal): Depois de lavar as garrafas, podes reutilizar o plástico para guardar água. - After washing the bottles, you can reuse the plastic to store water.

Depois de translates as after. In Portuguese, when you use a preposition (here de) before a verb, you must use the infinitive form. So instead of a gerund (like English washing), you say Depois de lavar.

Why is the verb lavar in the infinitive and not a conjugated form?

The structure Depois de + infinitive is fixed. You never conjugate lavar after depois de. The infinitive expresses the action in a general way:
• Depois de lavar as garrafas = After washing the bottles.

Why is podes used instead of pode or podem, and who is the subject?

Podes is the second-person singular form of poder (“to be able to”), meaning you can when speaking informally to one person (tu). In European Portuguese, tu + podes is common. The subject pronoun tu is omitted because the verb ending already shows who is doing the action.

Why isn’t the subject pronoun tu included before podes?

Portuguese is a pro-drop language: if the verb ending makes the subject clear, you drop the pronoun. Saying tu podes is not wrong, but in everyday speech you normally just say podes.

Why is o plástico singular when as garrafas is plural?

Here o plástico refers to the material (plastic) as a whole, not individual plastic pieces. It’s uncountable in this context:
• as garrafas (the bottles) are plural objects
• o plástico (the plastic) is a mass/substance you’re going to reuse

What does guardar mean and how is it different from armazenar?

Guardar generally means to keep or to store in everyday contexts. Armazenar can also mean to store, but is often used for larger quantities, warehouses or technical contexts. In a household setting, guardar água (store water) is more natural than armazenar água.

Can I replace podes reutilizar with podes usar de novo?

Yes. Reutilizar literally means reuse, and usar de novo means use again. Both convey the same idea:
• podes reutilizar o plástico
• podes usar o plástico de novo

Why is there a comma after garrafas?

When an adverbial phrase (Depois de lavar as garrafas) introduces the main clause, you separate it with a comma, just like in English:
“After washing the bottles, you can reuse the plastic to store water.”