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The fact that it " finally became our national character and main system after over half a century of international and domestic political transformation " is a stronger proof that it is the milestone for a new civilization resulted from the blood and sweat of thousands of proletarian revolutionary martyrs .
 date: half a century; cardinal: thousands
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: date, organization, person, geographical social political, national religious political, facility, cardinal, location, work of art, law, event, product, ordinal, percent, time, quantity, money, language 
Text: {0} 
Answer:
 date: half a century; cardinal: thousands