turtle back arch 圆穹顶

arch back 体后屈 ; 有弧度的底部

arch the back 弓背 ; 弓身

energy-saving back arch 节能后拱

arch one's back 弓背 ; 拱着腰

back of arch 拱背

back to arch 背反弓

back-bone style arch structure tent 脊骨式拱架帐篷

arch my back 拱起我的背