名詞 riverbed:

1. a channel occupied (or formerly occupied) by a river
   同義詞：river bottom

1. Sediment deposited by flowing water, as in a riverbed, flood plain, or delta.
   沖積層河床、洪水淹沒的平原或三角洲中的流水淤積所產(chǎn)生的沉積層
2. There are many pebbles on the riverbed.
   河床上有很多卵石。

riv.er.bed

n.（名詞）
The area between the banks of a river ordinarily covered by water.
河床：常被水覆蓋的一條河流兩岸之間的區(qū)域