The practice proves that PMS solves the longstanding problems with protecting the ecological balance of the abandoned quarry and is worthy of active popularization and application.
实践证明,PMS技术很好地解决了废弃采石场长期存在着的生态环保问题,应积极予以推广和应用。
A team of scientists came to this controversial conclusion by dating human footprints preserved by volcanic ash in an abandoned quarry in Mexico.