1
a crustacean
crustacean 是可数名词，复数形式为 crustaceans。
A crab is a crustacean.
螃蟹是一种甲壳纲动物。
甲壳纲动物
先理解核心含义，再看它在真实句子里的用法。
甲壳纲动物
a mainly aquatic arthropod with a segmented body and a hard outer shell
A crab is a crustacean.
螃蟹是一种甲壳纲动物。
甲壳亚门节肢动物,包括龙虾、蟹、虾、藤壶和潮虫等。
Any arthropod of the subphylum Crustacea, including lobsters, crabs, shrimp, barnacles and woodlice.
甲壳动物(多为水生节肢动物)
any mainly aquatic arthropod usually having a segmented body and chitinous exoskeleton
泛甲壳类节肢动物,除传统甲壳类外还包括六足动物。
Any arthropod of the clade Pancrustacea, which includes hexapods in addition to traditional crustaceans.
The crab is a crustacean that lives near the shore.
螃蟹是一种生活在海岸附近的甲壳纲动物。
Many crustaceans, such as shrimp and lobsters, are important to the fishing industry.
许多甲壳纲动物，如虾和龙虾，对渔业很重要。
We studied how a crustacean grows by shedding its old shell.
我们研究了甲壳纲动物如何通过蜕去旧壳来生长。
crustacean 是可数名词，复数形式为 crustaceans。
A crab is a crustacean.
螃蟹是一种甲壳纲动物。
泛指时常用复数形式。
Crustaceans live mainly in water.
甲壳纲动物主要生活在水中。
此处 crustacean 作形容词，意为“甲壳纲的”。
Crustacean shells are made of chitin.
甲壳纲动物的外壳由几丁质构成。
Not this
This animal is crustacean.
Use this
This animal is a crustacean.
crustacean 作名词表示“甲壳纲动物”时是可数名词，单数前需加冠词 a/an；中文“甲壳类”没有冠词，所以容易漏掉，导致句子缺少必要的冠词。
Not this
Crustacean is an important food source for many people.
Use this
Crustaceans are an important food source for many people.
crustacean 是可数名词，泛指整个类别的甲壳纲动物时要用复数 crustaceans，谓语动词也用 are；中文用“甲壳类”表达类别，但英语需用复数形式才能表示这一类动物。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
海洋甲壳类动物
Lobsters are marine crustaceans.
龙虾是海洋甲壳类动物。
淡水甲壳类动物
Crayfish are freshwater crustaceans.
小龙虾是淡水甲壳类动物。
甲壳类物种
Scientists discovered a new crustacean species in the deep ocean.
科学家在深海中发现了新的甲壳类物种。
可食用甲壳类动物
Crab is a popular edible crustacean.
螃蟹是一种常见的可食用甲壳类动物。
甲壳类动物的甲壳
The crustacean shell is made of chitin.
甲壳类动物的壳由几丁质构成。
Use crustacean naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
crustacean 开头 cr- 像 crust（外壳），虾蟹一身硬壳，正是甲壳纲动物。
语域：mixed 常见场景：biology textbooks、natural history museums、science documentaries 该词作名词时比较常见于生物学、科普教育等场合；日常口语里通常改用 shellfish、crab、lobster 等更具体的词。
发音匹配：station、nation、relation 与 crustacean 的重读部分 /eɪʃən/ 押韵。注意拼写相似的 ocean /ˈoʊʃən/ 和 musician /mjuˈzɪʃən/ 并不押韵，因为重读元音分别是 /oʊ/ 和 /ɪ/。
Dictionary facts from ECDICT, WIKTIONARY.