"I work in a hospital."
Translation:Lavoro in un ospedale.
Why would you not just the contraction of un'ospedale since hospital begins with a vowel?
Un' is the contraction of una before vowels; but ospedale is masculine, so its article is un (truncation of uno), not una.
This is my main gripe with DL (which I should stress is, on net, fantastic): we don't always learn the gender of a word the first time we see it. This is quite a big problem, because we end up making guesses about the gender, and can later forget whether our belief about the gender of a word is based on a guess or actual knowledge. That leads to far more confusion about gender than is necessary.