单选题 .  Doctors say anger can be an extremely damaging emotion unless you learn how to     41    with it. They warn that angry hostile feelings can     42    heart disease, stomach     43    , headaches, and     44    cancer. Anger is a normal     45    that we all feel     46    . Some people express anger     47    in a calm reasonable way. Others     48    with anger and scream and yell. But other people keep their anger     49    . They can not or will not     50    it. This is called repressing anger.     51    years many doctors thought that     52    anger was more dangerous to a person's     53    than expressing it. Doctors said that     54    the feeling to express the anger only makes the feeling     55        And this can lead to many     56    problems. Doctors thought a person could     57    these problems by letting the anger     58    , by expressing it freely. But recently some doctors     59    this. They said that people who express anger repeatedly and explosively become in fact     60    angry.41.