Listen to the passage and complete the following sentences (听短文,完成下列内容,每空格限填一词)
21. Now Hu Xincheng ________ ________ a machine for help when she has hard maths problems.
22. Each classroom building has ________ ________ one machine like this in Hu’s school.
23. In a very short time the machines will be put in ________ ________ schools in Yongkang.
24. Li Bing, a teacher of the school, had the idea ________ ________ the machine.
25. Ye Xiaochang can find answers to questions in many ________ ________ on the machine.