1
in one's briefcase
one's 可根据主语换成 his, her, my 等限定词。
He found the contract in his briefcase.
他在公事包里找到了那份合同。
公事包
先理解核心含义，再看它在真实句子里的用法。
公事包
a case with a handle, used for carrying papers, files, or books
He found the contract in his briefcase.
他在公事包里找到了那份合同。
用于携带文件的手提箱,尤指商务用。
A case used for carrying documents, especially for business.
带手柄的箱子；用于携带文件、书籍等
a case with a handle; for carrying papers or files or books
在Microsoft Windows中,一种支持自身与另一文件夹之间文件同步的文件夹。
In Microsoft Windows, a folder that supports file synchronization between itself and another folder.
He put the signed contract into his briefcase before leaving the office.
他离开办公室前把签好的合同放进了他的公事包。
She always carries a leather briefcase to work.
她总是带着一个皮公事包去上班。
My briefcase is too small for all these folders.
我的公事包太小了，装不下所有这些文件夹。
one's 可根据主语换成 his, her, my 等限定词。
He found the contract in his briefcase.
他在公事包里找到了那份合同。
full of 放在名词后，表示“装满……的”。
She arrived with a briefcase full of documents.
她带着一个装满文件的公事包来了。
with a briefcase 可直接修饰名词，表示“带着公事包的”。
A man with a briefcase was waiting outside.
一个拿着公事包的男人在外面等着。
Not this
He brings briefcase to the office.
Use this
He brings a briefcase to the office.
briefcase 是可数名词，单数形式前需要冠词或限定词；加 a 表示“一个公文包”。
Not this
There are three briefcase on the shelf.
Use this
There are three briefcases on the shelf.
briefcase 的复数形式是 briefcases；用 three 等数量词时，名词必须用复数。
Not this
She carries a suitcase to the meeting.
Use this
She carries a briefcase to the meeting.
briefcase 指装文件、书本的公文包，适合带去开会；suitcase 指旅行用的大行李箱，用在这里不符合语境。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
皮革公文包
He carried a black leather briefcase to the meeting.
他带着一个黑色皮革公文包去开会。
提着公文包
She always carries a briefcase to work.
她总是提着公文包上班。
打开公文包
He opened his briefcase and took out a folder.
他打开公文包，拿出一个文件夹。
装满文件的公文包
The lawyer arrived with a briefcase full of documents.
律师带着一个装满文件的公文包到达。
行政公文包
She received an executive briefcase as a gift.
她收到一个行政公文包作为礼物。
公文包里有什么？
In the 1994 film Pulp Fiction, Vincent Vega asks this about the mysterious glowing briefcase he and Jules have just taken from a gangster. It is one of the film's most famous questions and is often quoted.
在1994年的电影《低俗小说》中，文森特·维加这样问道，指的是他和朱尔斯刚从一个混混手里拿到的神秘发光公文包。这是影片中最著名的台词之一，常被引用。
Use briefcase naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
brief（摘要文件）+ case（箱子）→ 装文件的箱子，就是公事包。
语域：neutral 常见场景：商务办公、正式会议、日常通勤 通常用于商务或办公场合，是比较中性的日常用词，正式和口语中都可以使用。
The second syllable of 'briefcase' sounds exactly like 'case', so it rhymes with 'face', 'place', 'space', and 'base'. Note that the first syllable is pronounced /brif/, not like 'brief' (/briːf/) or 'brie' (/briː/). 'Suitcase' also rhymes and shares the same spelling '-case'.
Dictionary facts from ECDICT, WIKTIONARY.