back in time 時光倒流，回到從前back in the usa back in the saddle back in stride back in rocker [體育]后內(nèi)內(nèi)勾形后內(nèi)勾形back in loop change loop [體育]后內(nèi)單腳結(jié)環(huán)形back in circle [體育]后內(nèi)圓形back in a moment 馬上回來back in 后內(nèi)刃back hub 后視標(biāo)桿back hood yoke width [語言學(xué)]后帽育克back home again back hoe 反向鏟；反鏟挖土機(jī)back hearth [土木建筑工程]爐灰腔back haunch fillet of arch [交通運輸工程]護(hù)拱back haul [通信] 空載傳輸；返航，回送back hand welding [能源科學(xué)技術(shù)]反手焊接back hand back half of the stalls [藝術(shù)學(xué)]一樓觀眾席后座back ground 背景