1. The pilot found that the undercarriage could not be retracted. 驾驶员发现飞机的起落架不能缩回。
2. You may retract that statement. 你可以撤回那个声明。
3. Next, he pressed the side-clip of the pen, which can make the point of the pen retract. 接着，他按了一下可以让笔尖缩回去的圆珠笔侧面的夹子，这使得笔尖缩了回去。
英英解释
v.
1. formally reject or disavow a formerly held belief, usually under pressure
2. pull away from a source of disgust or fear
3. use a surgical instrument to hold open (the edges of a wound or an organ)
4. pull inward or towards a center
