How could you change a line into ray?

Answer 1

Like - um - in an infinite number of ways, I guess.

First: you can take a random point on the line and BAM. You have two rays with common point. Pointing in opposite directions. Infinitely unveiling [?].

Second: take two arbitrary points A and B from a given line or just freely in space. Create a ray from A to B and beyond. If you don't like what you've got, create a ray from B to A and beyond.

Two points are enough to define a ray, and I can't think of anything better.

Ditto.