题目选项分析

Archaeologists in Egypt have excavated a 5,000-year-old wooden hull that is the earliest surviving example of a "built" boat--in other words, a boat constructed out of planks fitted together--and that thus represents a major advance, in terms of boat-building technology, over the dugout logs and reed vessels of more ancient vintage.

Archaeologists in Egypt have excavated a 5,000-year-old wooden hull that is the earliest surviving example of a "built" boat--in other words, a boat constructed out of planks fitted together--and this has represented a major advance, in terms of boat-building technology, over the dugout logs and reed vessels of more ancient vintage.