retractv.缩回;收回;撤销
retractor support牵开器支撑器
retracting spring回动弹簧,释放弹簧,回程用弹簧
retractile spring复位弹簧
retracting motion回缩运动
retractable fiber收缩性纤维
retractor launcher收缩式发射器
retractive pruning回缩
retraction of head头仰缩
retraction mapping收缩映射
retractable bumper收放式尾撑杆