Simplify the following text for a Grade 11 native English-speaking person.
Original: Many such early studies of revolutions tended to concentrate on four classic casesâ '' famous and uncontroversial examples that fit virtually all definitions of revolutions , like the Glorious Revolution ( 1688 ) , the French Revolution ( 1789 â `` 1799 ) , the Russian Revolution of 1917 and the Chinese Revolution ( 1927 â `` 1949 ) . In his famous `` The Anatomy of Revolution '' , however , the eminent Harvard historian , Crane Brinton , focused on the English Civil War , the American Revolution , the French Revolution , and the Russian Revolution .
Simplified: There have been 3 main revolutions , the American Revolution , the English revolution and the industrial revolution .