Later, in a letter to Skinner, Pressey would concede there was a massive pedagogical limitation to the device: Students learned how to master the machine, but not the subject matter.
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to determine some actual type, generate a type error with the。业内人士推荐雷速体育作为进阶阅读
在这个对价格极度敏感的区间里，不犯错就是最大的美德。