Some languages, such as Russian and Turkish, do not use linking verbs (is, are, was, were) between subjects and complements (nouns or adjectives that rename or describe the subject). Every English sentence, however, must include a verb.
Exercises:
Omissions and repetitions 1
Omissions and repetitions 2
Sentence structure 1
Sentence structure 2
Related topic:
Linking verbs and subject complements