原文：
Travel American
Throughout their history, Americans have been people on the move（在行进中）. The early immigrants had to travel to get to the New World. Once they arrived, they settled（安顿） along the East Coast. But they weren't content to stay there. Explorers（探险家） and traders（商人） journeyed to the unknown western territories（领土）.Even today, Americans seem unable to stay put. Research says that the average American moves every five years.
Besides their habit of changing addresses, Americans are used to traveling. Some people make long-distance commutes（通勤） to work daily. Their jobs may even require them to take frequent （频繁的）business trips. Most companies provide an annual（一年一次的） vacation for their employees, and people often use that time to travel. Some people just visit friends or relatives in distant states. Others go on low-budget weekend excursions（短途旅行） and stay in economy motels. Camping out in the great outdoors appeals to adventurous（爱冒险的） types. Some travel in recreational vehicles（野营旅游车） to camp out in comfort, while others "rough it" （将就一下）by sleeping in tents（帐篷）.
本题答案：have been ；moves ；选A