❶center of gravity ❷heart;crux;core;focus 世界事务的～正从过去三个世纪以来一直所在的大西洋转向太平洋。The center of gravity of world affairs is shifting from the Atlantic,where it was lodged for the past three centuries,to the Pacific./工作～ focus of our work/问题的～heart (or crux)of the matter