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Parents and teachers both raised the idea of " ability streaming , " i.e. , different classes for different ability levels , to address the difficulties of large classes .
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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:
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