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be made of polyethylene
表示某种物品由聚乙烯材料制成时，常用 be made of 结构。
The bottle is made of polyethylene.
这个瓶子是由聚乙烯制成的。
聚乙烯
先理解核心含义，再看它在真实句子里的用法。
聚乙烯
a lightweight thermoplastic; used especially in packaging and insulation
The bottle is made of polyethylene.
这个瓶子是由聚乙烯制成的。
由许多乙烯单体键合而成的聚合物；用于厨房用具、容器等。
A polymer consisting of many ethylene monomers bonded together; used for kitchenware, containers etc.
一种轻质热塑性塑料,尤用于包装和绝缘。
a lightweight thermoplastic; used especially in packaging and insulation
Polyethylene is commonly used to make shopping bags.
聚乙烯通常用来制作购物袋。
The bottle is made of sturdy polyethylene, so it won't break easily.
这个瓶子由坚固的聚乙烯制成，所以不容易破裂。
Manufacturers often choose polyethylene for its flexibility and low cost.
制造商常因其柔韧性和低成本而选择聚乙烯。
表示某种物品由聚乙烯材料制成时，常用 be made of 结构。
The bottle is made of polyethylene.
这个瓶子是由聚乙烯制成的。
聚乙烯可直接放在名词前作定语，说明该名词的材质或类型。
Polyethylene film is widely used in packaging.
聚乙烯薄膜广泛用于包装。
描述聚乙烯的常见用途时，可用 be used in 后接应用领域。
Polyethylene is used in many household products.
聚乙烯用于许多家用产品。
Not this
The bottles are made of polyethylenes.
Use this
The bottles are made of polyethylene.
聚乙烯作材料讲时是不可数名词，不应该加 -s；只有指不同种类的聚乙烯时才用 polyethylenes。此处表示材质，用单数即可。
Not this
I bought a polyethylene.
Use this
I bought a polyethylene bag.
polyethylene 指材料而非可数物品，不能直接加 a。要表示“一个聚乙烯袋子”等具体物品，需要在后面加上 bag 这类可数名词。
Not this
The cup is made by polyethylene.
Use this
The cup is made of polyethylene.
汉语的“由……制成”容易让人误用 by，但英语中由原材料制成要用 made of 或 made from，而 made by 后接的是动作执行者。聚乙烯是材料，不是执行者。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
聚乙烯薄膜
The food is wrapped in polyethylene film.
食物用聚乙烯薄膜包裹。
聚乙烯袋
Please put the vegetables in a polyethylene bag.
请把蔬菜放进聚乙烯袋。
聚乙烯管
The plumber installed a polyethylene pipe.
水管工安装了一根聚乙烯管。
高密度聚乙烯
High-density polyethylene is used to make bottles.
高密度聚乙烯用于制造瓶子。
低密度聚乙烯
Low-density polyethylene is softer and more flexible.
低密度聚乙烯更柔软、更有弹性。
聚乙烯泡沫
The device is packed in polyethylene foam.
设备用聚乙烯泡沫包装。
聚乙烯，聚乙烯
Many Radiohead fans remember the B-side that repeats the word "polyethylene."
许多 Radiohead 歌迷都记得那首反复唱出“聚乙烯”的 B 面歌曲。
Use polyethylene naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
poly- 是“多”，ethylene 是“乙烯”；想象许多乙烯分子手拉手连成长链，就成了聚乙烯塑料。
语域：formal 常见场景：packaging、insulation 该词多为正式或技术用语，常见于产品说明、材料规格和工业文献中；日常口语中通常说“塑料”而少用“聚乙烯”。
聚乙烯 (polyethylene) 的重音在 -eth- 上，词尾 -lene 读作 /ˌlin/。与它押韵的有 ethylene (/ˈɛθəˌlin/) 和 methylene (/ˈmɛθəˌlin/)。注意 line (/laɪn/)、scene (/siːn/) 和 benzene (/ˈbɛnziːn/) 拼写看起来相近，但读音不同，不要把 -lene 读成 /laɪn/ 或 /siːn/。
Dictionary facts from ECDICT, WIKTIONARY.