A、They made them swim around their ships. B、They painted their images on some items. C、They hunted them in great numbers. D、They

Moderator:
    Good evening, ladies and gentleman. Today we are honored to have Professor Barnett who is an expert in dolphin study. And he will introduce to us the unique characteristics and living conditions of dolphins. Professor Barnett, please. Professor Barnett:
    Thank you for your introduction, Lisa. Well, one of the most intelligent animals on the planet is the dolphin. These unique animals have been regarded highly by humans for many centuries. In ancient Greece, if sailors saw dolphins swim by their ships when they were starting out on a voyage, they believed they would have good luck.
    One unique characteristic that makes them different from other sea animals is the way that they communicate. Dolphins use sound, touch and taste in order to learn about their world; however, unlike dogs, dolphins cannot smell. They use a whistle or sound waves to see and feel their way around their environment. This makes them different from many other sea animals and also helps them communicate with people.
    Another unique thing about dolphins is that the bones in their fins are similar to those in human arms and hands. However, the connective tissue that surrounds the bones forms a flipper instead of a hand with individual fingers. Even though dolphins live in the oceans, they do not drink the salt water around them. Their bodies absorb water from the wide variety of creatures they eat.
    Loving a dolphin is an easy thing to do but, unlike a dog or a cat, the dolphin cannot come home with you from the ocean. That is why many people like collecting dolphin souvenirs. One can find many such things in almost every shop around the world. Even the ancient people painted the images of dolphins on their vases.
    However, dolphins are sometimes hunted in places like Japan, in an activity known as dolphin drive hunting.
    Besides drive hunting, they also face threats from habitat loss and marine pollution. Dolphins have been depicted in various cultures worldwide. Dolphins occasionally feature in literature and film. Dolphins are sometimes kept in captivity and trained to perform tricks, but breeding success has been poor and the animals often die within a few months of capture. The most common dolphins kept are the killer whales and bottlenose dolphins.
    16.What makes dolphins different from other sea animals?
    17.Why do many people enjoy collecting dolphin souvenirs?
    18.What did ancient people do with dolphins?
    19.What happening to the dolphins?