The days of the week in Spanish
lunes - Monday
martes - Tuesday
miércoles - Wednesday
jueves - Thursday
viernes - Friday
sábado - Saturday
domingo - Sunday
el fin de semana - the weekend
In Spanish, days of the week are not capitalized: lunes, martes, etc. All of them are masculine. In order to make them plural, we just use the plural article (el martes, los martes), except for sábado and domingo: el sábado, los sábados; el domingo, los domingos.
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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.