Which of the following statements are true ?
(i) A line segment has no definite length.
(ii) A ray has no end point.
(iii) A line has a definite length.
(iv) A line ↔AB is the same as line ↔BA.
(v) A ray →AB is the same as ray →BA.
(vi) Two distinct points always determine a unique line.
(vii) Three lines are concurrent if they have a common point.
(viii) Two distinct lines cannot have more than one point in common.
(ix) Two intersecting lines cannot both be parallel to the same line.
(x) Open half-line is the same thing as ray.
(xi) Two lines may intersect in two points.
(xii) Two lines are parallel only when they have no point in common.