听力原文： 'We need plenty more seals', Oolak said as they parted. He added, 'But you don't shoot seal in water now for they are hard to get'. Two hours passed, during which Bob had heard Oolak's rifle crack four or five times. Bob decided to look for his companion and rejoin him. He climbed an ice pinnacle to look. It was a peaceful scene that met Bob's gaze. White ice stretched before him with little streams flowing across its surface. The low hills and open plains of ice were all bathed in golden sunlight. He did not see Oolak, but he became aware that the dogs had been howling for some time. It dawned on him that the entire team was in an uproar. When he glanced his way to see what the trouble was, his heart almost froze. Walking toward them was an immense whitish form, sleek head hanging low--a polar bear! The bear smelled a freshly-killed seal which Oolak had dragged to the sled, and it was this that he was seeking. To the clamor of the dogs he paid no more attention than if it were the buzzing of a fly. In his entire life the huge beast had never known fear, for the. polar bear is the ruler of the ice. He knows no enemies. According to the passage, it is not easy to get seal