例句與造句

1. Therefore, since B is the midpoint of, triangles ?% FEB and ?% CEB are congruent ( three sides ), which implies that the angles marked are congruent . ( The angle above E is vertically opposite angle " BEC . ) This means that a ray of light which enters the parabola and arrives at E travelling parallel to the axis of symmetry will be reflected by the line so it travels along the line, as shown in red in the diagram ( assuming that the lines can somehow reflect light ).
2. It's difficult to find vertically opposite angles in a sentence. 用vertically opposite angles造句挺難的