zeroperiod无上课,无节课

问题：zeroperiod无上课,无节课

答案：↓↓↓

陈光星的回答：

网友采纳　　应该根据上下文来看吧如以下、Thelanguagelearners'age:ageofzero,ageof6、7,ageof18(vocationalage),whicharethebounds,arethezeroperiodoflearning,perschoolperiodoflearning,schoolperiod...