Nature worked in our favor. During the early 15th century, radiocarbon levels were changing quite rapidly, so that allowed us to narrow the time frame.
大自然帮了我们大忙，15世纪早期，碳元素层变化活跃，使我们能缩短时间距离。
2
If you think of them as a picture frame for changing plants and trees, you'll see why selecting the right kinds of materials for your pathways, patios, stone walls and decorations is vital.
Corresponding to the bridge carrying-capacity changing theory, the application frame system is set up in the paper to provide the carrying capacity calculation and programming with guiding ways.