短語(yǔ)詞組短語(yǔ)bobbin thread lower thread 縫紉底線bobbin thread knife 底線剪刀bobbin thread pull off 底線拉出量Bobbin thread slipping out 底線滑脫Adjusting the bobbin thread tension 底線張力的調(diào)節(jié) 返回 bobbin thread