Minha rotina mudou quando eu passei a fazer exercício antes do trabalho.

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Breakdown of Minha rotina mudou quando eu passei a fazer exercício antes do trabalho.

• minha: my
• quando: when
• antes: before

Questions & Answers about Minha rotina mudou quando eu passei a fazer exercício antes do trabalho.

Why is it minha rotina and not meu rotina?

Because rotina is a feminine noun in Portuguese.

Possessive words must agree with the noun they describe:

• meu = my, for masculine singular nouns
• minha = my, for feminine singular nouns

So:

• meu trabalho = my job/work
• minha rotina = my routine

Why is it mudou?

Mudou is the third-person singular preterite form of mudar.

The subject is minha rotina, which is grammatically third-person singular, so the verb must match it:

• minha rotina mudou = my routine changed

The preterite is used here because it refers to a change seen as a completed event or turning point in the past.

Why do we use quando here?

Quando means when and introduces the time when something happened.

In this sentence:

• Minha rotina mudou = My routine changed
• quando eu passei a fazer exercício... = when I started doing exercise...

So quando connects the main event with the moment that caused or accompanied the change.