Dad drives me to school every day, and the road is parallel to the bridge deck. I'm thinking, if it's not parallel, the road will become narrower and narrower, and it's too late to stop in a narrow place, or the width is different, so it's easy to collide with the car opposite. If two cars enter from a wide place, it is easy to crash and traffic jam in a narrow place. And if the two sides are really not parallel, the two lines will form an acute angle, which is a dead angle, so if the road is long enough, it will always intersect in one place, so how can the car drive past?
We say that this situation is parallel, but how to describe the parallel positional relationship in our own words?
The book says that two straight lines that do not intersect in the same plane are called parallel lines, which can also be said to be parallel to each other. Grandpa said it should be two straight lines. But I think we should add a condition that the distance between two straight lines should be the same, that is, the width should be the same. There is a certain space and distance between the two straight lines. The upper line is parallel to the lower line and the lower line is also parallel to the upper line.
There are two situations in which two straight lines intersect in parallel in a plane. At the same time, there are various parallels and intersections in life. For example, some fountains are deliberately set to spray upwards in parallel, and some fountains are deliberately crossed to form various shapes. Moreover, there is a special verticality in the intersection, such as two adjacent sides of the blackboard, two adjacent sides of the book, and several verticality in the corner. Parallel and vertical phenomena are everywhere in our lives. As long as we are good at observing it, we can discover its mystery.