If you're in the jungle, it's about 500 meters. So if a kid bicycles home, or walks a few miles, they're going to be off the grid, so to speak.
如果你在丛林地带，这个距离大概是500米。就比方说，如果一个孩子骑车回家， 或者走远了几英里，那么他们将脱离这个网络。