1
it is a/the custom (for sb) to do sth
It is a custom to give gifts at Christmas.
圣诞节送礼是一种习俗。
习惯；风俗
先理解核心含义，再看它在真实句子里的用法。
习惯；风俗
a traditional or habitual practice
It is a custom to give gifts at Christmas.
圣诞节送礼是一种习俗。
经常重复的行为；许多人共有的行为方式；普通的方式；习惯的做法；生活或行为的方法。
Frequent repetition of the same behavior; way of behavior common to many; ordinary manner; habitual practice; method of doing, living or behaving.
习惯做法
accepted or habitual practice
习惯性地从同一供应商购买商品。
Habitual buying of goods from one same vendor.
长期习俗
a specific practice of long standing
It is a local custom to bow when greeting someone.
鞠躬问候是当地的一种风俗。
Our family has a custom of opening gifts on Christmas Eve.
我们家有在圣诞前夜拆礼物的习惯。
Different countries have different customs regarding table manners.
不同的国家在餐桌礼仪方面有不同的风俗。
It is a custom to give gifts at Christmas.
圣诞节送礼是一种习俗。
customs 用复数形式，指海关。
We had to go through customs at the airport.
我们不得不在机场通过海关。
The custom of shaking hands is widespread.
握手的习俗很普遍。
Not this
It's a custom for him to take a walk after dinner.
Use this
It's his custom to take a walk after dinner.
custom 表示个人习惯时通常用单数且带所有格，如 'my custom'；而 'a custom' 多指社会风俗。
Not this
The custom officer checked my passport.
Use this
The customs officer checked my passport.
表示海关时，必须用复数形式 'customs'，如 'customs officer'。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
当地风俗
It is a local custom to remove your shoes before entering a home.
进屋前脱鞋是当地的风俗。
古老习俗
The ancient custom of lighting a fire on the solstice is still observed.
冬至点火的古老习俗至今仍被遵守。
做某事的习惯
The custom of exchanging gifts at Christmas is widespread.
圣诞节交换礼物的习俗很普遍。
关税
You must pay customs duty on imported goods.
你必须为进口商品缴纳关税。
海关官员
The customs officer asked to see my passport.
海关官员要求查看我的护照。
遵循习俗
They decided to follow the custom and have a big family dinner.
他们决定遵循习俗，举办一次盛大的家庭聚餐。
店内习俗；惯例
At this pub, it's the custom of the house to buy a round for everyone on your birthday.
在这家酒吧，生日那天为大家买一轮酒是店里的惯例。
行业惯例
Returning unsold goods is a custom of the trade in the book industry.
退回未售出的货物是图书行业的惯例。
按照习俗；习惯上
By custom, the eldest son inherits the family estate.
按照习俗，长子继承家族产业。
习惯是第二天性。
It took a while, but now checking emails every morning is a custom that feels natural, proving that custom is a second nature.
虽然一开始需要时间，但现在每天早上查邮件已经成了自然习惯，证明了习惯是第二天性。
习惯让我们对一切习以为常。
After living in the noisy city for years, the constant traffic sounds became a custom that no longer bothered him, showing that custom reconciles us to everything.
在这个嘈杂的城市住了多年后，持续的车流声成了一种习惯，不再困扰他，表明习惯让我们对一切习以为常。
Use custom naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
联想：custom（习惯）与customer（顾客）相关，顾客有购物习惯。
多用于表示社会或群体的传统习惯或常规做法，语境中性，常见于日常生活、文化讨论及正式场合。
复数形式customs可指海关
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.