[Hemospectrum]

Yes. For example, if you wanted to tell a stranger "that person is a police officer," the most natural translation is probably "ano hito wa keikan desu." In other contexts, you might replace "desu" with the informal "da" or the ultra-polite "de gozaimasu" (or "de gozaru" if you're a samurai). In practice you wouldn't say it too often. Other grammatical structures (like "-te iru") are more appropriate counterparts to maybe 75% of English sentences involving "to be."

It is nonetheless grammatically possible to contrive every sentence to end in "desu." This is an unusual habit, though. It's a little like beginning every utterance in English with "it seems" or "Simon says."