high value low weight cargo英 [haɪ ˈvæljuː ləʊ weɪt ˈkɑːɡəʊ]美 [haɪ ˈvæljuː loʊ weɪt ˈkɑːrɡoʊ]高值轻量〈价高质轻〉货物经济