In kindergartens,gas masks are added unobtrusively to the pile of toys so they become a familiar sight,but only the teachers are instructed in their use.

• 在幼儿园，防毒面具被悄悄地放在了一堆玩具中，这是为了让孩子们对它感到熟悉。但是只有老师知道使用方法。