Learn Italian: L'uomo adulto continua il progetto fra un mese. - The adult man continues the project in a month.

When talking about how much time will pass before a future event happens, Italian uses fra or tra. If you used in un mese, it would mean the action takes a month of continuous effort to complete, rather than starting one month from now.

Can I use tra instead of fra in this sentence?

Yes! Tra and fra are completely interchangeable. They both mean "in" for future time, or "between". Italians usually just choose whichever sounds better with the surrounding words to avoid tongue twisters. Here, tra un mese is just as correct.

Why is the verb continua in the present tense if the action happens in the future?

In Italian, it is very common to use the present tense to talk about the near future, as long as there is a time phrase like fra un mese that makes the timeline clear. You could also use the future tense (continuerà), but the present tense is very natural here.

Is adulto an adjective or a noun here?

In this sentence, it acts as an adjective describing uomo (man). However, just like in English, adulto can also be used as a noun on its own, so you could drop uomo and just say l'adulto (the adult).