短語(yǔ)詞組短語(yǔ)back of foot 足跗back one foot snake 倒單腳;后單腳back and foot 用背和腳攀登巖裂back of foot height 足背高go back on foot detail 步行回去back -foot follows up half-step 跟步on the back foot 受到威脅 返回 back foot