More nouns we can use with regular verbs
la carta - the letter
el email / el correo electrónico - the email
el mensaje de texto - the text message
el libro - the book
el idioma - the language
Progress, Vol. 1
Progress, all volumes
Interleaving
Drilling one topic until it feels easy is tempting, but mixing different topics together builds more flexible, durable knowledge. The variety forces your brain to work harder, and that's what makes it last.