Rivers in Japan, however, have smaller and steeper drainage areas, making these rivers less navigable, because their waters are flowing more steeply down to the sea.

然而，日流流域面积更小、更陡，导致这些流不太适合航，因为它们水流向大海坡度更大。

Bump is a small hill or small increase in the road, and dip is a small hole or a small decrease in the road or the street or the freeway or wherever it is that you are traveling.

Bump 是小山路小坡度，而 dip 是路、街高速公路您行驶任何地方小坑小坡度。