Now a more accurate method has been found.It involves bolting iron plates to the walls of tunnels at regular intervals and placing sledgehammers nearby.是什么意思_Now a more accurate method has been found.It involves bolting iron plates to the walls of tunnels at regular intervals and placing sledgehammers nearby.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句