例句：
The axis of a circle is its diameter.
圓的對(duì)稱中心線就是直徑。
He used a rope to mark off the circle.
他用一根繩子把這個(gè)圈圍了起來。
She walked clockwise around the circle.
她繞著圈順時(shí)針走。
The line cuts the circle at two points.
那條線與圓相交于兩點(diǎn)。
She walked the horse round in a circle.
她牽著馬兜圈子。