【文章內(nèi)容簡(jiǎn)介】
ound to form a smoother area so we can pass. The road is so bumpy and rough, with holes here and there and rocks lying all over. When we drive along this road, we have to be very careful, having a firm grip on the steering wheel, ready for a sudden turn or a large boulder that may appear any second. However, when we drive on a highway, everything bees different. The road is smooth, straight, and visible. Since there is no unseen obstacle, we may lower our guard, relax a bit, and loosen our grip on the steering wheel. One may even think, if we only have to drive on a smooth straight road like this highway, why would we need a steering wheel? Nevertheless, one cannot foresee the future. Accidents do happen. For example, a car may suddenly