During the design of backstop, especially the design of the key part allotype stone roller is not deep, the study is still relatively simple now, the method of research is still relatively backward.是什么意思_During the design of backstop, especially the design of the key part allotype stone roller is not deep, the study is still relatively simple now, the method of research is still relatively backward.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句