The Pentagon has invested in something called smart dust, little microsensors the size of specs of dust that you could scatter on people without them knowing it, and then use it to track their location.

五角大楼投资了一种叫做智能尘埃的东西，这种微型传感器的大小与尘埃规格相当， 你可以在人们不知情的情况下将其散布在人们身上， 然后用它来追踪他们的位置。