[填空题] Most people feel lonely sometimes. But it usually only lasts between a few minutes and a few hours. This kind of loneliness is not (36)________. In fact, it is quite normal. For some people though, loneliness can last for years. Now (37)________ say there are three different types of loneliness. The first kind of loneliness is (38)________ This is the most common type. It usually disappears quickly and does not require any special attention. The second kind, (39)________ loneliness, is a natural result of a particular situation-for example, a family problem, the death of a loved one, or moving to a new place. Although this kind of loneliness can cause (40)________ problems, such as headaches and sleeplessness, it usually does not last for more than a year. The third kind of loneliness is the most (41)________ Unlike the second type, chronic loneliness usually lasts more than two years and has no specific cause. People who (42)________ habitual loneliness have problems (43)__