1949年时波恩还是个无足轻重的小城市。In 1949 Bonn was a small, insignificant city.牛津和德国的波恩结成了友好城市。Oxford is twinned with Bonn in Germany.你真是个大旅行家 啊 !一分钟在巴黎, 下一分钟又到了波恩.You certainly get around! Paris one minute, Bonn the next....
当管受到挤压时,胶凝体便从微小的孔被挤入.When the tube is squeezed the gel is forced through tiny holes.无 宏观 缺陷水泥已成为高性能胶凝材料学科的重要研究方向.Macro - defect - free cements have become an important orientation of high performance cementitious materia...