"Bob is a translator."
Why are these kinds of exercises not spoken? It would be helpful to hear the pronunciation of the sentences when clicking on them.
For new Arabic learners out there, there is no articles such as "a", "an", "the", also there is no "am" in Arabic either, i had the same problem when i am being taught from a friend of mine in Egypt
I'd say there is a "the", that's ال connected to the word. Without it, this sentence is a sentence, Bob is a translator. If there is an ال, then this would be Bob the translator - not a sentence, but a reference to what person exactly you had in your mind.