It has its obscure and unpretentious beginning ; its quite stretches as well as its rapids ; its periods of drought as well as of fullness 其源头，隐隐约约，并不引人注目;其流势,时而平缓,时而湍急;其水情,有汛期,也有枯谒期
3.
Given any configuration of the river and the branched into which it may divide , as well as any number of bridges , determine whether or not it is possible to cross each bridge exactly once 如已知一条河以及这条河可能分成的支流流势图，此外还知道河上有若干座桥，试判定是否可能有一条能通过每座桥恰好一次的路线。
4.
Abstract : variations of flow pattern , flow velocity in deep poo l and side bar , mainstream thread , and water surface , caused by excavation project , are investigated by two - dimensional mathematical model in an orthogonal curvili near coordinate system . the change of bed - load transport rate , and redeposition r ate are predicted . the influences of the excavation project on navigation are ana lyzed . grid - type and flat - type excavation alternatives are proposed and discuss ed 文摘:采用正交曲线坐标系下的河道平面二维数学模型，研究了嘉陵江何家碛边滩采砂后河道流势、流态、滩槽流速、主流位置、水面高程及比降的变化规律，预测了采砂方案完成后卵石推移质输沙率变化及其对航道的影响，并对格形开挖和平整开挖方案进行了比较分析
