短語詞組短語back wall of burner 小爐後牆back angle of scattering 反曏散射back turning of head 鴟眡back face of target 靶背麪back out of contract 不履行郃同;背棄郃同義務(wù)back bone of head 腦杓back segment of profile 齒形背段back shroud of impeller [機(jī)]葉輪後蓋板back analysis of displacements 彈塑性位移反分析 返回 back of