noun [具体名词] 骑车
Bicycling is good exercise; besides, it does not pollute the air. 骑自行车时一种很好的运动，而且，还不污染空气。
verb [vt. 及物动词] vt. 骑自行车运送 vi.骑脚踏车（bicycle 的现在分词）
Bicycling was a great way to get the kids out of the house and into the fresh air without spending any money. 骑自行车是个好方法，不用花一分钱就能让孩子们走出家门，呼吸新鲜空气。
