1
be infectious
表示具有传染性。
The virus is highly infectious.
这种病毒传染性很强。
有传染性的, 易传染的
先理解核心含义，再看它在真实句子里的用法。
有传染性的, 易传染的
able to be passed from one person to another, causing infection
The virus is highly infectious.
这种病毒传染性很强。
由进入宿主身体的病原体(如细菌、病毒、寄生虫或朊病毒)引起的；常通过多种途径(如接触、飞沫、空气、水、食物、污染物或血液)在宿主之间传播。
Caused by an agent that enters the host's body (such as a bacterium, virus, parasite, or prion); often, also, transmitted among hosts via any of various routes (for example, contact, droplet-borne, airborne, waterborne, foodborne, fomite-borne, or bloodborne).
能够感染他人；能传播病原体。
Able to infect others; capable of transmitting pathogens.
迅速从一个人传播到另一个人。
Spreading quickly from one person to another.
Her laughter was so infectious that everyone in the room started laughing.
她的笑声太有感染力了，房间里的每个人都笑了起来。
The doctor warned that the disease is highly infectious and spreads through droplets.
医生警告说这种疾病有高度传染性，通过飞沫传播。
His infectious enthusiasm motivated the whole team to work harder.
他富有感染力的热情激励了整个团队更加努力。
表示具有传染性。
The virus is highly infectious.
这种病毒传染性很强。
作定语修饰疾病。
Measles is an infectious disease.
麻疹是一种传染病。
比喻意义，形容情绪等有感染力。
Her infectious laughter filled the room.
她富有感染力的笑声充满了房间。
表示持续状态。
The bacteria can remain infectious for hours.
细菌可在数小时内保持传染性。
Not this
He is infectious with the virus.
Use this
He is infected with the virus.
错误地将infectious用作表示“被感染”的意思。infectious形容疾病或病原体具有传染性，而形容人“被感染”应使用动词的过去分词infected，搭配介词with。
Not this
The infectious of the disease is high.
Use this
The infectiousness of the disease is high.
错误地将形容词infectious当作名词使用。表示“传染性”的名词形式是infectiousness，而非形容词infectious。应使用名词infectiousness。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
传染病
Vaccination helps prevent the spread of infectious diseases.
疫苗接种有助于防止传染病的传播。
有感染力的笑声
Her infectious laughter filled the room.
她有感染力的笑声充满了房间。
有感染力的微笑
He greeted everyone with an infectious smile.
他带着有感染力的微笑和每个人打招呼。
有感染力的热情
The coach's infectious enthusiasm motivated the team.
教练有感染力的热情激励了队伍。
传染源
The lab identified the infectious agent as a virus.
实验室确定传染源是一种病毒。
有感染力的笑声
Her infectious laughter filled the room, making everyone smile.
她那有感染力的笑声充满了房间，让每个人都笑了起来。
有感染力的微笑
He greeted everyone with an infectious smile that instantly put them at ease.
他用一个有感染力的微笑向每个人打招呼，立刻让他们放松下来。
有感染力的热情
The teacher's infectious enthusiasm for history made the class exciting.
老师对历史有感染力的热情让课堂变得激动人心。
Use infectious naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
infect + ious = 病菌扩散，极易传染。
语域：mixed 常见场景：医学、日常比喻 通常用于医学领域描述疾病传染性，也常见于比喻用法（如笑声、热情等具有感染力），两者均较常见。
通常用于描述疾病或情绪等具有传染性的特质，可直接修饰名词或作表语。
Dictionary facts from ECDICT, WIKTIONARY.