Psychologists suggest that to cure cruelty

The main use of studying history, expressed in the passage, is that

1. 
   it enables us to discover the reasons underlying present events
   
2. 
   people can get knowledge about their ancestors, from whom they descended
   
3. 
   decision makers can plan the future by taking past events as examples
   
4. 
   people can draw lessons from past events so as not to make the same mistakes
   

2. 
   The writer warns that when applying to the past for the solution of present or future events
   

1. 
   one has to be careful to choose events in the past which are very similar to the present situation
   
2. 
   one should have a good knowledge of both past and present
   
3. 
   one has to pay special attention to whether the sample event is in the distant or the near past
   
4. 
   one shouldn't ignore the essential changes in society over the years
   

1.