Perilous rock is one of main geologic disasters in mountain area of China.Safe net system is a passive control technique for rockfall in recent years.是什么意思_Perilous rock is one of main geologic disasters in mountain area of China.Safe net system is a passive control technique for rockfall in recent years.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句