Divide the sides of the first bundle in half so that it’s the shape of an X. Cut a second bundle of yarn into shorter lengths than the first (mine were 4″ shorter) and tie.
Cut the sweet potatoes in half lengthwise, then cut each half into 4-inch lengths.
将甜薯纵切一半,然后每一半切成四英寸长。
3
When the projecting distances of two gauges on the incident wave direction equal half of the incident wave lengths or time it, there will be a singular problem.