1. The cat had retractile claws that it could extend for climbing trees.
猫具有可伸缩的爪子，可以用来爬树。

2. The telescope has a retractile lens that can be extended or retracted for focusing.
这个望远镜有一个可伸缩的镜头，可以用来调焦。

3. The retractile feature of the retractable pen allows for easy storage and transportation.
可收缩的笔的可缩回功能使得存放和携带非常方便。