1
[noun] occurs in [place]
occur in 常用来表示元素或物质存在于某处。
Phosphorus occurs in phosphate rocks.
磷存在于磷酸盐岩石中。
磷
先理解核心含义，再看它在真实句子里的用法。
磷
a reactive nonmetallic chemical element that occurs in phosphate rocks and in all living cells, and exists in several allotropic forms
Phosphorus occurs in phosphate rocks.
磷存在于磷酸盐岩石中。
A chemical element (symbol P) with an atomic number of 15, that exists in several allotropic forms.
Phosphorus is used in the production of matches.
磷被用来制造火柴。
Plants need phosphorus from the soil to grow well.
植物需要土壤中的磷才能良好生长。
White phosphorus is highly reactive and must be stored under water.
白磷反应性很强，必须存放在水下。
occur in 常用来表示元素或物质存在于某处。
Phosphorus occurs in phosphate rocks.
磷存在于磷酸盐岩石中。
occur as 表示以某种形式存在，as 后接名词或名词短语。
Phosphorus occurs as organic phosphates in living cells.
磷以有机磷酸盐的形式存在于活细胞中。
be + 形容词 可用来描述物质的化学性质，如反应性。
Phosphorus is highly reactive.
磷非常活泼。
Not this
Phosphorous is a chemical element.
Use this
Phosphorus is a chemical element.
phosphorus 是名词，表示元素磷；而 phosphorous 是形容词，意为“含磷的”。此处需要名词作主语，因此应使用 phosphorus。注意词尾 -us 为名词，-ous 为形容词。
Not this
The match head contains a phosphorus.
Use this
The match head contains phosphorus.
chemical element phosphorus 指物质时是不可数名词，前面不能用不定冠词 a/an，也不能加复数。这里应去掉 a，直接用 phosphorus 表示“磷”。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
白磷
White phosphorus ignites spontaneously in air.
白磷在空气中自燃。
红磷
Red phosphorus is used in the striking surface of matchboxes.
红磷用于火柴盒的摩擦面。
磷循环
The phosphorus cycle is essential for plant growth.
磷循环对植物生长至关重要。
磷含量
This fertilizer has a high phosphorus content.
这种肥料磷含量很高。
磷水平
Doctors monitor phosphorus levels in patients with kidney disease.
医生监测肾病患者体内的磷水平。
Use phosphorus naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
磷会发光。记住 phosphorus 开头 phos，像夜幕里的鬼火一闪一闪。
语域：neutral 常见场景：chemistry class、scientific paper、industrial chemistry 作为化学元素名称（磷），通常用于学术、教学或工业语境，日常对话中较少出现。
物质名词通常不可数；词典列有复数 phosphoruses，异体 phosphori，仅在指多种形态等罕见场合使用。
Dictionary facts from ECDICT, WIKTIONARY.