求翻译：理论必定来源于实践，同时又必须回归实践、接受实践的检验。国际贸易实务在实际应用中遇到新的问题，原有的理论不能适应其发展，就会产生阻碍，最终会导致理论的发展。是什么意思？

Theory must be derived from the practice, they also must return to practice, the test of practice. International trade practice in the practical application of new problems, the original theory can not meet its development, will have obstacles, will eventually lead to development of the theory.

Theory comes from practice, and at the same time we must return to practice, and the test of practice. International trade practice in practical applications with new problems, the country's original theory cannot be adapted to its development, the result will be impeded, will eventually lead to the

The theory originates surely from the practice, simultaneously must return the practice, accept the practice the examination.The international trade practice meets the new question in the practical application, the original theory cannot adapt its development, can have the hindrance, finally can cau

Theory comes from practice, and must return to practice, to practice examination. New problems encountered in international trade practice in the practical application, the original theory does not fit into their development, will create obstacles, will eventually lead to a theory of development.

The theory must come from and practise, while must return to practice, accept the test of practice. The practice of international trade meets the new problem in the practical application, the original theory can't adapt to its development, will hinder, will cause the development of the theory finall