中国似乎已经长期处于停滞状态，……更大规模的国外贸易，一定能大大增加中国的制造产品，大大提高中国制造业的生产力。China seems to have been long stationary, … A more extensive foreign trade … could scarce fail to increase very much the manufactures of China, and to improve very much the productive powers of its manufacturing industry. ——亚当.斯密
