中美贸易之所以能迅速发展，根本原因在于两国经济具有极大的互补性。这种互补性，很大程度上来自两国经济资源条件、经济结构以及消费水平存在着很大的差异。中国是最大的发展中国家，市场广阔，发展迅速，劳动力成本低，但资金短缺、科技和管理相对落后。美国是最大的发达国家，经济总量大，资本充足，科技发达，但劳动力成本高。这种差异性和互补性（interlocking qualities），将在今后长期存在，在经济全球化的大背景下显得更加突出。

  The reason for such rapid growth in China-US trade is, in the final analysis, the high degree to which the economies complement each other. This neat fit, to a large extent, stems from their differences in economic resources, economic structures and consumption levels. China is the world's largest developing country with a huge market, fast development and low labor costs, but short of capital and relatively backward in technology and management skills. On the other hand, the US is the world's largest developed country, big in economic size, with abundant capital, and advanced in science and technology. But the cost of labor in the US is high. These diverse yet interlocking qualities will remain for a long time, and are likely to feature more prominently in the ongoing economic globalization. This, in my view, is the material basis for the sustained and rapid expansion of China-US trade.