When students got their textbooks at the beginning of the year at San Mateo High School, they also received the Yondr pouch, a locking device for their phones.当圣马特奥高中的学生在年初拿到课本的时候，他们也收到一个用来锁住手机的Yondr袋子。The phone slides into it and gets locked through a magnetic device. Its not unlocked again until the final bell rings. The procedure ing concerned pletely lost on their phones, some not socializing at all paring yourself to other women on your feed and it definitely takes a toll on your self-image, said Lea Wadhams another senior at SMHS.“你不断与你关注的其他女性进行比较，这肯定会对你的自我形象产生严重不良的影响，”圣马特奥高中的另一位高年级学生莱亚·万德汉姆斯说道。