1
sb be in
in 作表语，表示“在家或办公室”；通常不放在名词前作定语。
I called but she wasn't in.
我打了电话，但她不在（家/办公室）。
在…里面；在室内的；在家的
先理解核心含义，再看它在真实句子里的用法。
在…里面；在室内的；在家的
Located inside something, especially indoors, at home, or at one's workplace.
I called but she wasn't in.
我打了电话，但她不在（家/办公室）。
位于室内,尤其是在家或办公室
Located indoors, especially at home or at one's office or place of work.
位于某物内部
Located inside something.
在比赛区域内
Falling or remaining within the bounds of the playing area.
插入或装入某物中
Inserted or fitted into something.
This brand is really in this season.
这个品牌这个季节真的很流行。
She only hangs out with the in crowd.
她只和那些时髦的人出去玩。
He has an in joke with his friends.
他和朋友们有个内部笑话。
in 作表语，表示“在家或办公室”；通常不放在名词前作定语。
I called but she wasn't in.
我打了电话，但她不在（家/办公室）。
非正式用法，表示“流行、时髦”；反义词为 out。
Long dresses are in this year.
今年流行长裙。
用于描述潮水处于最高水位附近；反义词为 out。
The tide is in and the beach is narrow.
涨潮了，海滩很窄。
Not this
I am in home.
Use this
I am in.
错句把汉语“在家”逐词译成 in home；home 不能直接作介词 in 的宾语。形容词 in 作表语时本身就表示“在室内/在家/在办公室”，所以应省略 home，说 I am in。
Not this
This style is in the fashion now.
Use this
This style is in now.
错句把“流行”误译为 in the fashion；in fashion 是固定搭配，不加 the，而形容词 in 本身就表示“时髦、流行”，可直接作表语。去掉 the fashion，用 be + in 即可。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
在家；在室内
Sorry, Mr. Chen is not in right now. Can I take a message?
抱歉，陈先生现在不在家。您需要留言吗？
参与；知晓（秘密、计划等）
Are you in on the plan to surprise the teacher?
你参与给老师惊喜的计划吗？
与…关系好；与…交往
He is in with the company's top managers.
他和公司高层管理人员关系很好。
流行的事物；时尚
Electric bikes are the in thing around town these days.
如今电动自行车在城里很流行。
涨潮
We can't cross the sandbank because the tide is in.
我们不能穿过沙洲，因为涨潮了。
收成已收割完毕
Once the harvest is in, the village holds a big feast.
收成收割完之后，村里会举办盛大的宴会。
即将遭受（尤指不愉快的事）
If you keep teasing the dog, you're in for a nasty bite.
你要是继续逗那条狗，准会被狠狠咬一口。
参与；知情
Everyone was in on the surprise party except Maya.
除了玛雅，每个人都知道这个惊喜派对。
与…关系密切；深得…欢心
He's in with the right people, so he always hears about job openings first.
他和说得上话的人关系好，所以总能最先听说工作机会。
我是时髦圈子里的一员。
The song 'The In Crowd' used the word 'in' to mean fashionable or popular.
歌曲《The In Crowd》中用“in”表示时髦、受欢迎的。
Use In naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
想象“in”像一扇门：字母i是门框，n是门板，推门进去就是“在室内”，形容词表“室内的、在家的”。
语域：neutral 常见场景：at home、at the office in 作形容词表示“在室内、在家或办公室”时属于中性用词，正式与非正式场合都常见，多用于询问或说明某人是否在场。
以上单词均与 in /ɪn/ 押韵：pin /pɪn/、tin /tɪn/、win /wɪn/、sin /sɪn/、thin /θɪn/、bin /bɪn/。注意：拼写以 -ine 结尾的词（如 pine /paɪn/、fine /faɪn/）发音为 /aɪn/，虽形似但读音不同。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY, WORDNET.