stroke centerline

例句：

1. 1. She carefully stroked the painting with her finger.
   她用手指仔细地抚摸着这幅画。
2. 2. Theartist used a brush to stroke the canvas.
   艺术家用刷子在画布上作画。
3. 3. The children were playing with theirtoys, stroking them gently.
   孩子们正在玩他们的玩具，轻轻地抚摸它们。