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For four years , from 1937 to 1941 , China fought against Japan on its own , and it even counterattacked .
 four years, from 1937 to 1941, China, Japan
Please list all entity words in the text that fit the category. Output format is "word1, 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:
 four years, from 1937 to 1941, China, Japan