Researchers have already identified three different types of loneliness. The first type of loneliness is ＿＿（36）＿＿ . This is the most common type. It usually ＿＿（37）＿＿ quickly and does not require any special attention. The second type, situational loneliness, is a natural result of a particular situation—for example, a divorce, the death of a loved one, or moving to a new place. Although this type of loneliness can cause ＿＿（38）＿＿ problems, such as headaches and sleeplessness, it usually does not last for more than a year. Situational loneliness is easy to understand and to predict. The third type is the most ＿＿（39）＿＿ . Unlike the second type, chronic loneliness usually lasts more than two years and has no specific cause. People who experience ＿＿（40）＿＿ loneliness have problems socializing and becoming close to others. Unfortunately, many chronically lonely people think there is little or nothing they can do to improve their condition.