vertical opening

• 垂直洞口

vertical opening的用法和样例：

例句

1. He wormed himself through the opening.
   他慢慢地爬过洞口。
2. Quickly pulling the remaining pieces from the opening, Silas gazed into the void.
   塞拉斯迅速地拨开残留在洞口的碎石，向空洞里张望。