A standard one. Replacement during the first year if all rules for proper use have been followed.
有一个原则,如果在一年内符合各种使用规定,就可更换。
Byrd now knew that he would be able to reach the South Pole which was 300 miles away, for there were no more mountains in sight.
伯德这时知道他能够顺利飞抵300英里以外的南极了,因为前面再没有山了。