They are reminders of Lake Superior's commercialshipping history.
它们是苏必利尔湖商业航运史的遗物。
2
A gun like this would also be useful for stopping pirate attacks against commercialshipping.
像这样的电磁炮同样也可用于阻止海盗袭击商用船只。
3
The U. S. Navy has a significant presence in the region, especially in the Gulf of Aden - a busy commercialshipping lane off the northern coast of Somalia.