跨越国境的运输服务是一种十分重要的无形贸易。国际运输涉及各种不同的方式，例如，海轮、飞机、火车、汽车和内河船只运输。然而，其中最重要的是海轮。
【正确答案】：Transportation service across national boundaries is an important kind of invisible trade. International transportation involves different means of transport such as ocean ships，planes，trains, trucks and inland water vessels. However, the most important of them is maritime ships.
【题目解析】：参见教材P83。
