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The relations between dolphins and human beings have long ( I  been      surprising) people. These relations (2 have lasted) for thousands of years. Pictures of dolphins (3 were used) to decorate the coins of ancient Greeks. Sailors (4 - considered) the presence of dolphins near ships to be good luck. Now dolphins (5 are trained) and they (6 take) part in performances that both children and grown-ups (7 like). When you (8 - spend) your holiday on the Black Sea coast you (9 - can) see dolphins (10 play) near the shore. They usually ( 11- come) early in the morning and before sunset. They (12 - are considered) to be our friends. No one has ever (13 seen) a dolphin attack human beings.