retractv.缩回;收回;撤销
retractable ramp收放式跳板
retraction valve回缩阀
retractable fibre收缩性纤维
retractable probe可收起的受油探管
retraction stress收缩应力
retractable guide可撤导板
retractable claws能收缩的爪
retracting stroke倒[逆]转,(返)回(行)程
retractable arbor能自由伸缩的芯棒
retraction reflex头后仰反射
"cats have retractile claws"