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mountainous + noun
作定语修饰名词，常指地形；也可用于比喻，如 mountainous waves（滔天巨浪）、mountainous debt（巨额债务）。
The mountainous region is popular with hikers.
这个多山地区很受徒步者欢迎。
多山的
先理解核心含义，再看它在真实句子里的用法。
多山的
having hills and crags
The mountainous region is popular with hikers.
这个多山地区很受徒步者欢迎。
此处仅指“多山的”一义；不表示“如山的”或“巨大的”。
多山的；以山脉为特征的；山一般的；(地形)崎岖的；岩石的。
Having many mountains; characterized by mountains; of the nature of a mountain; rough (terrain); rocky.
有丘陵和峭壁的
having hills and crags
似山的,尤其指规模巨大；庞大的；高耸的。
Resembling a mountain, especially in size; huge; towering.
像山一样大且令人印象深刻的
like a mountain in size and impressiveness
The village is surrounded by mountainous terrain, so the roads are steep and winding.
村庄被多山的地形环绕，所以道路陡峭蜿蜒。
AI contextual example
Driving through the mountainous region took much longer than we expected.
开车穿过山区花费的时间比我们预期的长得多。
AI contextual example
They built the new hiking trail across the mountainous landscape.
他们在多山的风景中修建了新的徒步小径。
AI contextual example
mountainous waves
如山般的巨浪
WordNet
作定语修饰名词，常指地形；也可用于比喻，如 mountainous waves（滔天巨浪）、mountainous debt（巨额债务）。
The mountainous region is popular with hikers.
这个多山地区很受徒步者欢迎。
作表语，说明主语的地貌特征。
The area is mountainous and sparsely populated.
该地区多山，人口稀少。
与 become 连用强调状态变化。
The terrain becomes mountainous near the border.
靠近边境时地形变得多山。
Not this
The area is very mountain.
Use this
The area is very mountainous.
mountain 是名词，不能直接作表语描述地形；应改用形容词 mountainous（多山的）。
Not this
The mountainous in the north are covered with snow.
Use this
The mountains in the north are covered with snow.
mountainous 是形容词，不能当名词指代山脉；表达“山脉”要用名词 mountains。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
崎岖多山的地形
The hikers struggled to cross the mountainous terrain.
徒步者艰难地穿越崎岖多山的地形。
多山地区
The mountainous region receives heavy snowfall in winter.
这个多山地区冬季降雪很大。
多山的国家
Nepal is a mountainous country in South Asia.
尼泊尔是南亚的一个多山国家。
多山的景观
The photograph captures a beautiful mountainous landscape.
这张照片拍下了美丽的多山景观。
多山的道路
Driving on mountainous roads requires caution.
在多山道路上驾驶需要小心。
Use mountainous naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
mountain（山）+ ous 形容词后缀，想象群山连绵不绝、到处都是山，就是“多山的”。
语域：neutral 常见场景：地理描述、旅行指南、新闻报道 「mountainous」为中性表达，多用于描述地理特征或地形，较常见于书面语和新闻、旅行介绍等场合，日常口语中使用频率相对较低，但并无特定正式或非正式限制。
常作定语或表语，如 a mountainous region / The terrain is mountainous。
Dictionary facts from ECDICT, WIKTIONARY.