航道

waterway; channel; shipping lane; air route; navigational route; sea lane

上的

superior

狭窄

narrow; poky; cramped; confined; confining

部分

part; piece; portion; section; segment; division; slice; aspect; zone; facet; partial; fractional; some; partially; partly; in part; semi-; demi-; sub-; pt; pt. (short for part)