Parallel straight lines are straight lines which, being in the same plane and being produced indefinitely in both directions, do not meet one another in either direction.
平行直线是在同一平面内的直线，向两个方向无限延长，在不论哪个方向它们都不相交。
Parallel straight lines are straight lines which, being in the same plane and being produced indefinitely in both directions, do not meet one another in either direction.
平行直线是在同一平面内的直线，向两个方向无限延长，在不论哪个方向它们都不相交。
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