Pierre is a 25﹣year﹣old penguin（企鹅）at the California Academy of Sciences．Due to his old age，he was losing his feathers，which made him feel too cold to swim in the pool．Therefore
When people hear a president speak, they seldom think about others helping to shape the presentation（报告）. Today, however, presidents depend on writers such as J. Terry Edmonds to help t
的图像经过第一、三象限，则k的取值范围是 ． 