"I am working at the library since January."

Translation: Eu estou trabalhando na biblioteca desde janeiro.

[LotSparham]

The English practice sentence is grammatically incorrect. My suggestion would be that DL replace it with MattCunnin7's suggestion.

[vsandl]

The English is grammatically incorrect. If you use "since" then you must use a past tense. "I have worked here since..." or "I have been working here since...".

[vivalahumanidad]

Is this the correct use of the continuous tense here or would another version be more appropriate in Portuguese?

[Paulenrique]

In Portuguese it works quite well, but in English the "present perfect (continuous)" works better....

[MattCunnin7]

Right. The original English is awkward at best. It would be better to say: "I have been working at the library since January."

[Paulenrique]

For sure your suggestion works better in English =)

[PennyDovale]

When do you use "sou" and when do you use "estou"

[pinkybrainy]

What would be the meaning of this sentence when using simple present (eu trabalho na biblioteca desde janeiro) instead of the continuous?