例句：
The axis of a circle is its diameter.
圓的對稱中心線就是直徑。
He used a rope to mark off the circle.
他用一根繩子把這個圈圍了起來。
She walked clockwise around the circle.
她繞着圈順時針走。
The line cuts the circle at two points.
那條線與圓相交於兩點。
She walked the horse round in a circle.
她牽着馬兜圈子。
