sulcus to crus of helix

例句：

1. 1. The carpenter made a notch in the wood for the handle.
   木匠在木头上做了一个凹槽，用来固定把手。
2. 2. The old lady had a deep crease on her forehead.
   老妇人额头上有一道深深的皱纹。
3. 3. The book has a crease at the center of the page.
   这本书书页中间有一道折痕。