0 a long, thin stretch of water that is artificially made either for boats to travel along or for taking water from one area to another -- 運河；渠
1 a narrow tube through which air, fluid, or other substances can pass -- 管，道
In order to turn the deserts into fertile and productive land, engineers built an 800-mile canal.
Swellings at the base of each canal, the ampullae, are visible.
The canals were cemented over, the fields disappeared and only some tiny rural features remained.
As the canal system no longer provided the means of obtaining water, a series of wells were dug parallel to the old canal.
