Yes. Tense is not marked on the verb in Klingon, so without context this could be any tense. Sometimes, a sentence like this is meant to be general and not specific. Sometimes, the tense will be clear in the context of the conversation. Or sometimes, it can be made clear within the sentence by adding a time stamp (for instance, "yesterday" or "tomorrow"). Since Duolingo's exercises don't include context, exercises like this accept translations into past, present, or future.
Is there a progressive form, or maybe a present imperfect aspect, that expresses "I am working"?
If you Read the notes on the lessons you will see it says - progressive form to be covered later.
Thank you. In my joy at seeing this offered, I am unwisely starting on my telephone, which does not have access to Tips and Notes.
If one opens a Chrome window on the Android phone, one can access all the programs available on the laptop version, but the Tips and Notes are not available and a few of the hover translations are not visible. It was not that much of an inconvenience for Czech or Romanian, but it was pretty impossible to do Guarani that way, and I think it will be for Klingon as well.