Siete is not the reason this construction is feminine. Instead, the full construction is "a las siete horas (y media)", lit. "to the seven hours (and a half)". The hidden horas here is the reason why las is used.
Note that "at one o'clock" uses the singular article: "a la una". That's because you're only talking about one hour here.
You don't say "I work at Fridays" in English either. :)
Clock times are expressed with the construction "a la(s) xx (hora(s))", literally translating as "to the xx hour(s)". It makes about as much sense as saying "xx o'clock" in English.
Clock times take a, daytimes take por or en, specific days don't take prepositions, and months, seasons, and years take en.
The hover is not meant to be used in that way. The hover tells you that work can be appropriate in some sentences. Trabajar is also a verb so I have found it more useful when describing what you are working at. For example, Yo trabajo a la fábrica. I work at the factory. The hover is a generalization of all uses and is used to get your thinking cap on. In this case they wanted you to use it a a noun, mi trabajo (my job).
It can be either. If you say "ir a [location]", like here, it means that you're going somewhere, so both "to go to [location]" and "to be going to [location]" are appropriate translations.
- Voy a la escuela. - I am going to school. / I go to school.
But you can also use that verb for the phrasal future tense, "ir a [verb]", which has the same meaning as the English "to be going to [verb]".
- Voy a aprender mucho. - I am going to learn a lot.
That is what we would say here in the US as well, but I think as someone said above they want to emphasize that el trabajo is a noun. To others who wonder why their possible answer was not accepted - this is not google translate which is not always accurate. In duo each possible answer must be individually entered and the program looks at what has been entered only. That´s why every possible translation doesn´t work. I type seven thirty and that works so I stick with it througout duo.
This would make sense if this person had more than job (one at the office and one at the factory). "I'm going to my job" (at the office instead of my job at the factory). The job or work can be described as a noun or as a verb. But like everyone's saying, in English (US and UK), it's an award sentence and it's not commonly said on its own like that.
I am not here to complain nor to give any corrections but I am just surprised how Spanish drastically gave impact to us Filipinos especially in our language. I'm a Filipino and I speak Bisaya (a local dialect here in PH) Most of our words do have borrowed words from Español. I guess I ain't having a hard time learning and memorizing Spanish words at the first place.
Using number symbols for clock times is okay, and Spanish mostly does it the same way, writing "a las 7:30" or similar.
Duolingo prefers using words, though, especially when you're dealing with the Spanish sentence, since you're supposed to learn how to spell and pronounce the numbers.
Out of curiosity, are there other ways that 7:30 might be spoken in Spanish?
Obviously English may just be seven thirty, or it may be half after/past seven, or possibly even nineteen-thirty if the person speaking is using 24-hour time and talking about 7:30 PM. Does Spanish have similar variations? I would assume there’s at least some 24-hour time equivalent even if it may not be particularly prevalent.