two point cross

The subsolar point will cross every latitude between these two extremes exactly twice per year.

太阳直射点每年恰好两次穿越这两个极端之间的所有纬度。

As anyone who has done any cross-country hiking will tell you, there are two data points which must be in-hand before a course can be plotted: the starting point and the ending point.

如同所有完成过越野徒步旅行的人告诉您的，在绘制行程之前必须掌握两个数据点：出发点和终点。

A two-dimensional model of such a universe would look like a sphere. It's impossible to have parallel geodesics (straight lines on a curved surface) — the two lines will cross at some point.

这样的2维宇宙模型就像是球体，不可能出现平行的测地线(测地线是曲面上的直线)——两直线必然在某点相交。