a scab forms over sth
指伤口愈合时结痂，常与 over 或 on 连用。
A scab formed over the cut within a few days.
几天之内，伤口上就结了一层痂。
工贼；破坏罢工者；（马铃薯）疮痂病；植物疮痂病；（羊）疥癣；（铸件表面的）结疤
A dry crust that forms over a cut or wound as it heals.
伤口、水疱或脓疱愈合时形成的硬痂。
An incrustation over a sore, wound, vesicle, or pustule, formed during healing.
罢工期间工作(或提供工人)的人
someone who works (or provides workers) during a strike
兽疥癣,尤指绵羊身上的。
The mange, especially when it appears on sheep.
愈合皮肤病变的结痂状表面
the crustlike surface of a healing skin lesion
马铃薯疮痂病,由链霉菌引起的块茎表面产生凹陷和损伤的病害。
Any of several different diseases of potatoes producing pits and other damage on their surface, caused by streptomyces bacteria (but formerly believed to be caused by a fungus).
普通疮痂病,一种相对无害的马铃薯病害,由疮痂链霉菌引起。
Common scab, a relatively harmless variety of scab (potato disease) caused by Streptomyces scabies.
多种危害栽培植物的真菌病害之一,形成暗色痂状斑点。
Any one of various more or less destructive fungal diseases that attack cultivated plants, forming dark-colored crustlike spots.
铸件表面的轻微不规则突起,由模具部分破损造成。
A slight irregular protuberance which defaces the surface of a casting, caused by the breaking away of a part of the mold.
卑鄙、肮脏、微不足道的人。
A mean, dirty, paltry fellow.
The union members called the replacement worker a scab.
工会成员称那名为罢工顶替的工人为工贼。
用法提示：名词scab指在罢工期间工作的人，含贬义
He picked at the scab on his knee, making it bleed again.
他抠了抠膝盖上的痂，结果又流血了。
用法提示：名词scab指伤口愈合时结的痂
The doctor said not to remove the scab because it protects the wound.
医生说不要揭掉那层痂，因为它保护着伤口。
用法提示：名词scab指愈合中的皮肤损伤表面的硬壳
指伤口愈合时结痂，常与 over 或 on 连用。
A scab formed over the cut within a few days.
几天之内，伤口上就结了一层痂。
pick at 表示反复用手抠、挠某处。
Try not to pick at the scab, or it may leave a scar.
尽量不要抠痂，否则可能会留下疤痕。
此义指罢工期间上班的人，带强烈贬义。
The workers called him a scab for taking a job during the strike.
工人们骂他是工贼，因为他在罢工期间接受了工作。
crust 泛指面包皮、地壳等硬外层，范围比 scab 广；指伤口上的痂时 scab 更直接、常用。
grammar · medium
易错句子Don't pick the scar on your knee; it will bleed again.
正确表达Don't pick the scab on your knee; it will bleed again.
scar 指伤口愈合后留下的永久疤痕，scab 指愈合过程中在伤口表面形成的痂，会自行脱落。这里说的是正在结、被抠掉还会再流血的痂，所以要用 scab。
grammar · medium
易错句子There is scab on my elbow.
正确表达There is a scab on my elbow.
scab 作“痂”讲时是可数名词，单数形式前必须有冠词或其他限定词。汉语名词没有冠词，学习者容易漏掉不定冠词 a，写成 There is scab。
此反义词仅对应 scab 的“工贼、破坏罢工者”义项；在“伤口痂”等义项下没有常用直接反义词。
scar 指伤口愈合后留下的永久性痕迹；scab 指愈合过程中伤口表面暂时结成的硬痂，痂脱落后才可能留下 scar。
crust 泛指坚硬的外层，如面包皮、地壳，也可指伤口表面结的硬层；scab 专指伤口愈合时结的痂，医学和日常语境中都更精确。
scabies 是由疥螨引起的传染性皮肤病（疥疮）；scab 指伤口愈合时结的痂，两者拼写和读音相近，但所指完全不同。
抠痂
Don't pick a scab even if it itches.
即使发痒也不要抠痂。
结痂（过程）
Scab formation is a normal part of wound healing.
结痂是伤口愈合的正常过程。
痂组织
The scab tissue protects the new skin underneath.
痂组织保护下面的新皮肤。
马铃薯疮痂病
Potato scab can make the tubers unsightly.
马铃薯疮痂病会使块茎不好看。
顶替罢工者的人；工贼
The factory hired scab labor during the strike.
罢工期间工厂雇用了顶替罢工者的人。
痂是伤口愈合时在表面形成的硬壳。
痂是皮肤愈合过程中的自然产物。
痂主要由干涸的血和血清构成。
感染可能导致伤口结痂或加剧结痂。
水疱破裂后也可能形成痂。
结痂；愈合
The wound should scab over within a week.
伤口应在一周内结痂。
老是抠痂；反复揭开伤疤
Stop picking at that scab—it will heal faster if you leave it alone.
别再抠那块痂了，你不碰它好得更快。
Dictionary facts from ECDICT, WIKTIONARY.