山区人有这样一种体会：背着沉重的东西，上山比较容易，而下山却很困难，越着急越难走，太急了还会跌个倒栽葱。于是有人干脆掉过头来，倒退着往下走。这样，可以把身子弯得很低，甚至可以用手支撑在地上分解压力，而又绝不至于失衡，和上坡比较起来，脚步移动要轻松得多。这 Mountain people have such an experience: carrying heavy things, the mountain is relatively easy, but the mountain is very difficult, the more anxious the more difficult to go, too anxious to fall a downturn. So someone simply turned his head and backed away. In this way, the body can be bent very low, and even can be used to support the ground to break down the pressure, but never unbalanced, compared with the uphill, the pace of moving much easier. This