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a/an + incisor
incisor 是可数名词，单数前通常要用冠词 a/an。
An incisor is used for biting.
门牙用于咬切。
门牙；切牙
先理解核心含义，再看它在真实句子里的用法。
门牙；切牙
a front tooth used for cutting or gnawing
An incisor is used for biting.
门牙用于咬切。
哺乳动物口腔前部窄刃的牙齿,位于犬齿之间,用于切割；人类每颌有四颗。
A narrow-edged tooth at the front of the mouth of mammals, between the canines and adapted for cutting; in humans there are four in each jaw.
用于切割或啃咬的牙齿；位于上下颌的前部
a tooth for cutting or gnawing; located in the front of the mouth in both jaws
The dentist said my new incisor is growing in straight.
牙医说我的新门牙长得正了。
Rabbits use their sharp incisors to gnaw on carrots and wood.
兔子用它们锋利的门牙啃胡萝卜和木头。
She chipped her upper incisor when she fell off the bike.
她从自行车上摔下来时碰缺了上颌门牙。
incisor 是可数名词，单数前通常要用冠词 a/an。
An incisor is used for biting.
门牙用于咬切。
表示上下门牙整体时通常用复数 incisors。
Adults have eight incisors.
成年人有八颗门牙。
her/their 等限定词加复数 incisors 常用来指某人的门牙。
She lost one of her incisors.
她失去了一颗门牙。
Not this
I have two incisor in my mouth.
Use this
I have two incisors in my mouth.
incisor 是可数名词，受 two 修饰时应用复数形式 incisors，不能省略 -s。
Not this
The average adult has 32 incisors.
Use this
The average adult has 32 teeth.
incisor 仅指门牙，成人共有 8 颗；表示口腔内全部牙齿时应用 teeth，不能用 incisors 泛指所有牙齿。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
上颌门牙
The upper incisors are often the first teeth you see when someone smiles.
上颌门牙通常是微笑时最先看到的牙齿。
下颌门牙
The lower incisors are usually a little narrower than the upper ones.
下颌门牙通常比上颌门牙稍窄一些。
中切牙（中间的门牙）
Her central incisors are perfectly straight.
她的中切牙非常整齐。
侧切牙（门牙两侧的牙）
The lateral incisors are located right next to the central incisors.
侧切牙紧挨着中切牙。
恒切牙（成人门牙）
Permanent incisors begin to replace baby teeth around age six or seven.
恒切牙在六到七岁左右开始替换乳牙。
锋利的门牙
A beaver's sharp incisors can cut through wood.
河狸锋利的门牙能咬断木头。
Use incisor naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
联想：incisor 里的 cis 像 scissors（剪刀），门牙像剪刀一样切断食物。
语域：formal 常见场景：dental clinic、anatomy textbook、medical report incisor 是解剖学/牙科术语，多用于医疗、生物教材等正式或专业场合；日常口语中更常说 front tooth。
The genuine rhymes are divisor, advisor, visor, and miser, all ending in /-aɪzɝ/. Watch out: scissor (/ˈsɪzɝ/) and incision (/ɪnˈsɪʒən/) look related but sound different.
Dictionary facts from ECDICT, OCTANOVE, WIKTIONARY.