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，日本的河流流域面、陡，导致这些河流不太适合航，因为它们的水流向大海的大。

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 是山丘或道路的，而 dip 是道路、街道或高速公路或您行驶的任何地方的坑或。