字母'y'底部向下延伸的部分被称为降部。

The bottom extension of the letter 'y' is called a ___descender.

这名登山者是一位经验丰富的下降者，能够自如地在陡峭的岩壁上移动。

The climber is an experienced ___descender who can move freely on steep rock faces.

救援人员使用下降器安全地将伤员从悬崖上降下来。

The rescue team used a ___descender to lower the injured person safely down the cliff.