V-ERG
（使）缩回;（使）缩入;（使）收起
When a part of a machine or a part of a person's body retracts or is retracted, it moves inwards or becomes shorter.
例句
Torn muscles retract, and lose strength, structure, and tightness.
撕裂的肌肉会收缩，丧失原来的力量、结构和紧实度。
...when the aircraft's wheels were retracted.
当飞机的轮子收起来的时候