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be a carcinogen
be a carcinogen 用于说明某物质属于致癌物，'known' 可修饰 carcinogen。
This chemical is a known carcinogen.
这种化学品是已知的致癌物。
致癌物；致癌物质
先理解核心含义，再看它在真实句子里的用法。
致癌物；致癌物质
a substance that produces cancer
This chemical is a known carcinogen.
这种化学品是已知的致癌物。
一种能引起癌症的物质或因子。
A substance or agent that can cause cancer.
任何产生癌症的物质。
any substance that produces cancer
Smoking introduces many carcinogens into the body.
吸烟会把许多致癌物质带入体内。
The laboratory is testing whether this chemical is a carcinogen.
实验室正在测试这种化学物质是否是致癌物。
Some food additives have been classified as carcinogens.
一些食品添加剂已被归类为致癌物。
be a carcinogen 用于说明某物质属于致癌物，'known' 可修饰 carcinogen。
This chemical is a known carcinogen.
这种化学品是已知的致癌物。
classify...as a carcinogen 是及物动词搭配，as 后接名词作宾语补足语。
The agency classified the additive as a carcinogen.
该机构将这种添加剂列为致癌物。
be exposed to 后接复数 carcinogens，表示被动接触或暴露于致癌物。
Workers may be exposed to carcinogens at the plant.
工人在工厂可能接触到致癌物。
Not this
This chemical is carcinogen.
Use this
This chemical is a carcinogen.
carcinogen 是可数名词，单数形式前需要加冠词 a/an；汉语“致癌物”可泛指，但英语中 a carcinogen 才能表示“一种致癌物”。
Not this
Smoke contains many carcinogen.
Use this
Smoke contains many carcinogens.
many 后接可数名词复数，carcinogen 的复数是 carcinogens；汉语名词没有复数变化，容易漏掉 -s。
Not this
Carcinogen foods should be avoided.
Use this
Carcinogenic foods should be avoided.
修饰名词 foods 应用形容词 carcinogenic（致癌的），carcinogen 是名词（致癌物），不能直接作定语修饰 foods。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
已知致癌物
Asbestos is a known carcinogen.
石棉是已知致癌物。
疑似致癌物
The additive is a suspected carcinogen.
这种添加剂是疑似致癌物。
致癌物暴露
Long-term carcinogen exposure increases the risk of cancer.
长期暴露于致癌物会增加患癌风险。
含有致癌物
Some processed meats contain carcinogens.
一些加工肉类含有致癌物。
列为致癌物
The agency classified the substance as a carcinogen.
该机构将这种物质列为致癌物。
Use carcinogen naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
把 carcinogen 看成 carci-（像 cancer 的开头，联想到癌）+ -gen（生成），联想“生成癌的物质”，即致癌物。
语域：formal 常见场景：医学文献、健康新闻、监管文件 carcinogen 属于正式、书面化的科技词汇，多用于医学、化学或公共卫生等专业场合；日常口语中较少使用。
carcinogen and these -gen words share the unstressed ending /dʒən/, but the stressed vowels differ, so they do not fully rhyme. Genuine full rhymes are rare; treat spellings like hydrogen, oxygen, and nitrogen as useful lookalikes that sound different.
Dictionary facts from ECDICT, WIKTIONARY.