In Washington, President Trump laid a wreath at the memorial to the Pentagon victims and later sounded a warning.

在华盛顿，总统特朗普为五角大楼遇难者敬献花圈，随后向极端分子发出警告。

Through chemicals, grass is sounding a warning call to nearby plants, which start putting up their defensive dukes, getting ready to protect themselves from damage.

通过化学物质，草向附近的植物发出了警告，这些植物开始建立它们的防御机制，准备保护自己免受伤害。