Along with stop, drop and roll, some states are teaching students to 'Stop and don't touch that gun.' Arkansas, Tennessee and Utah passed laws requiring schools to teach children as ...

“Sawfly（锯蜂）” 是一种与黄蜂相似的昆虫，这种昆虫会切开植物并把自己的卵产在切口处。苏格兰赫瑞-瓦特大学的研究人员一直在研究雌性锯蜂怎么知道如何做出这种独特的切割，从而避免杀死或损伤植物。