Culture and DIscovery

Protecting yourself from PM2.5

作者：21st

A MASK is an absolute (绝对的) must when you go outdoors in foggy weather. This is especially true for people in northern China, where heavy smog (雾霾) has been lingering (徘徊) for the past few months. But is your mask really protecting you?

点击阅读全文

对本期电子报订户、有效期内的VIP教师会员和本学期高二尊享卡用户，我们开放所有内容：
如果您拥有以上权限，请点这里登录；
订阅电子报，请点这里；
激活VIP教师卡，请点这里；
激活21英语尊享卡，请点这里。