Sentence:  Imagine a country where children do nothing but play until they start compulsory schooling at age seven. Then, without exception, they attend comprehensives until the age of 16. <WSD>Charging</WSD> school fees is illegal, and so is sorting pupils into ability groups by streaming or setting. 
Meaning of the word marked with <WSD> tags:  to require payment (of) (a price or fee, for goods, services, etc.)