By the 19th century, the canal fell into disrepair thanks to neglected maintenance, a major flood, and heavy pollution.
到19世纪，由于疏于维护，大洪涝和污染严重，大运河的命运陷入塌毁的境地。
2
It not only solves the problem of frost heaving of canal but also declares the maintenance cost, improves the efficiency of routing, and saves water resources.
既解决了工程抗冻胀问题，节省工程维修费用，又大大地提高了灌溉渠道输水效率，节约水资源。
3
Conclusion Maintenance of width of the aural canal and prevention of lateral healing of the transplantated tympanic membrane were crucial in the treatment of congenital aural atresia.