TOEFL單詞短語學習：

erosion n. 侵蝕，腐蝕 (noun): wearing away of the soil by wind and water
- Erosion is often a natural process by which many geological formations are created.

breathtaking adj. 驚人的；驚險的；令人激動的 (adjective): incredible, awesome, amazing
- The scenic views of the valley were breathtaking.

strenuous adj. 緊張的；費力的；奮發的；艱苦的；熱烈的 (adjective): physically difficult
- We took a very strenuous hike that lasted all day, and I'm exhausted.

wash n. 洗滌；洗的衣服；化妝水；沖積物 (noun): a dry stream bed
- We followed the wash for about a mile until we reached the mouth of the canyon.

leave word 留言 (verb): notify or inform
- She didn't leave word where she would be traveling, and now her family is really worried.

sturdy adj. 堅定的；強健的；健全的 (adjective): strong
- You need to wear sturdy hiking boots for this trip because we will be going through some rough terrain.

dehydrated adj. 脫水的 (adjective): suffer from lack of water
- The lost hiker was extremely dehydrated when she was found wandering in the desert.