a knock at/on sth
指敲击门、窗等发出的声音；接门时 at 和 on 都很常用。
I heard a knock at the door.
我听见有人敲门。
敲击声；敲门声
knocks — plural of knock
猛击；重击；批评；抨击；爆震；敲缸；安打；击打球；饥饿感；饿得难受
An abrupt rapping sound, especially one made on a door, or the sound of knocking in an engine or bearing.
突然的敲击声,如硬物撞击木头的声音。
An abrupt rapping sound, as from an impact of a hard object against wood.
敲击声
the sound of knocking (as on a door or in an engine or bearing)
猛烈的撞击。
A sharp impact.
负面批评
negative criticism
爆震,一种在火花点火发动机中因自燃引起的异常燃烧；也指与之相关的特有敲击声。
Preignition, a type of abnormal combustion occurring in spark ignition engines caused by self-ignition; also, the characteristic knocking sound associated with it.
猛击
a vigorous blow
击出的球,尤其是成为安打的球。
A ball hit into play, especially one that becomes a hit.
饥饿敲击的同义词。
Synonym of hunger knock.
I heard a loud knock on the door at midnight.
我半夜听到一声响亮的敲门声。
用法提示：此处knock作名词，意为'敲击声'，指敲门的声音。
AI contextual example
The film took several knocks from reviewers for its weak plot.
这部电影因情节薄弱受到评论家的多次批评。
用法提示：此处knock作名词，意为'负面批评'，指批评意见。
AI contextual example
He gave the metal pipe a sharp knock with a hammer.
他用锤子猛敲了一下金属管。
用法提示：此处knock作名词，意为'猛击'，指猛烈的打击。
AI contextual example
指敲击门、窗等发出的声音；接门时 at 和 on 都很常用。
I heard a knock at the door.
我听见有人敲门。
表示身体某部位受到的猛烈撞击，前面常加 hard、nasty 等形容词。
He got a nasty knock on the head.
他头上被重重地撞了一下。
引申指遭受打击或损失，多用于股价、信心、生意等抽象事物。
The company's shares took a knock after the announcement.
消息公布后，公司股价受到打击。
grammar · medium
易错句子I heard knock at the door last night.
正确表达I heard a knock at the door last night.
knock 作名词是可数名词，单数形式前必须加不定冠词 a/an 或其他限定词；汉语说“敲门声”时不带任何冠词，因此学生常把这个 a 漏掉。
grammar · medium
易错句子There were three knock at the door.
正确表达There were three knocks at the door.
可数名词表示两个或更多数量时要用复数形式 knocks；汉语名词本身没有单复数变化，学生容易忘记在数词后加 -s。
grammar · medium
易错句子He got a knock at the head.
正确表达He got a knock on the head.
表示身体某部位遭到撞击时用介词 on（a knock on the head）；at 用于门、窗等位置，学生常把 a knock at the door 中的 at 过度泛化到身体部位。
敲门声
I heard a knock at the door.
我听到了敲门声。
响亮的敲击声
A loud knock echoed through the hallway.
响亮的敲击声在走廊里回荡。
尖锐的敲门声
A sharp knock on the door made her jump.
尖锐的敲门声让她吓了一跳。
遭受打击
The company took a knock after the scandal.
丑闻之后，公司遭受了打击。
沉重的打击
He received a heavy knock to his pride.
他的自尊心受到了沉重打击。
经受批评
In politics, you have to take the knocks.
政治生涯中，你必须经受批评。
敲木头以求好运（迷信）
I haven't been sick all year, knock on wood.
我一年都没生病，敲敲木头（希望好运继续）。
住手；别闹了
Knock it off, you two are being too loud.
别闹了，你们两个太吵了。
击倒；使不省人事
The boxer knocked out his opponent in the first round.
拳击手在第一回合就击倒了对手。
敲、敲、敲！谁在那儿？
From Shakespeare's Macbeth, spoken by the Porter in Act 2, Scene 3. This line is famous as a representation of comic relief after a murder, and it has been referenced in many films and jokes.
出自莎士比亚的《麦克白》，由门卫在第二幕第三场说出。这句台词是谋杀场景后的喜剧缓解，被许多电影和笑话引用。
如果你想我，就在天花板上敲三下
Lyric from the song 'Tie a Yellow Ribbon Round the Ole Oak Tree' by Tony Orlando and Dawn (1973). The line is a secret signal between lovers, and it became a cultural reference for coded communication.
出自托尼·奥兰多与黎明乐队1973年的歌曲《在古老的橡树上系一条黄丝带》。这句歌词是恋人之间的秘密信号，成为暗号沟通的文化参考。
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Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY, WORDNET.