这条山间小径陡峭而富有挑战性。

The mountain ___trail was steep and challenging.

在森林小径上徒步数小时后，我们终于找到一片空地休息。

After hiking for hours on the forest ___trail, we finally found a clearing to rest.

黄石国家公园有数百英里标识清晰的小径。

Yellowstone National Park has hundreds of miles of well-marked ___trails.