The only real restrictions imposed on private schools were that they must run their admissions on a first - come - first - served basis and promise not to charge top - up fees ( most american voucher schemes impose similar conditions ) 对私立学校唯一真正的的限制就是必须按“先来先得”的原则招收学生,并且要承诺不收取附加费(大多数美国补助计划也附加类似条件) 。