自然保护区设立后，原则上不得撤销；因特殊情形失去保护价值的，经原批准设立该自然保护区的人民政府批准，可以撤销。
Now it is easy to use the Pythagorean Theorem to estimate the distance between two points:
，这一点在PDF资料中也有详细论述
# so a cross-thread watcher could stall until something else
It was a severe limitation.
В ведомстве призвали граждан быть осторожными.