阅读理解A Most of what we call nightmares are simple extreme reactions and fear that go with uncomfortable dreams. Often we are awoken by a nightmare and there can be a strong feeling of sadness, anger or guilt, but usually fear and anxiety.Nightmares may have several causes,including drugs,medicine, illness, trauma or they may have no related cause. Often they occur when there is pressure in one’s waking life,and when major life changes are occurring.