"He writes a letter, I read the newspaper."
Translation:El scrie o scrisoare, eu citesc ziarul.
The indefinite article is a separate word, not a prefix, but yes, the definite article is reflected at the end of the word. Sometimes it looks like a suffix, sometimes it alters the word.
(a) man = (un) barbat
the man = barbatul
(a) woman = (o) femeie
the woman = femeia
water = apă
the water = apa