1.最常见的含义是打电话给某个单位，打进电话：
Call in to this radio station and ask the governor a question.打电话到这个电台，问负责人一个问题。
People call in and just spill their guts about whatever's bothering them on the job or in a relationship.
人们打进电话，就是要将工作或感情上的所有困扰倾诉出来。
He would call in advance to make sure there was no alcohol at the party ．
他会提前打电话来确认聚会上没有酒。
I called in at the office on the off chance that you would still be there.
我打电话给办公室，想看看你是否可能还在那里。
Emma has just called in sick.
埃玛刚才打电话来请病假了。
The director has just called in to say that she'll be late.
主任来电话说她要迟些时候来。
2.call sb in for sth=call in sb for sth或call sb in to do =call in sb to do sth召(找)来或叫来某人做某事
The manager called Karen in for a private meeting. 经理叫凯伦来开个私人会议。
Will you call the kids in for lunch?
把孩子们叫进来吃午饭好吗？
The police called in Gary for questioning.警察把加里叫来问话。
We will have to call a heart specialist in for a consultation. 我们得请一位心脏专家来会诊。
We called in another specialist for an opinion.我们请了另一位专家征求意见。
We had to call in a plumber to unblock the drain.
我们只得叫个管子工来疏通下水道。
Call in an architect or surveyor to oversee the work.
找个建筑师或监理员来监工。
Builders were called in to make the building safe.
召来建筑工加固这栋大楼。
A lawyer is often called in to write a will.
律师常被请来写遗嘱。
Public health officials were called in to inspect the premises.
公共卫生官员奉召来视察了建筑物。
They called in a psychologist to give an independent opinion.
他们征询一位心理学家的独立意见。
The military was/ were called in to deal with the riot.
已调来军队平息暴乱。
Troops were called in to subdue the rebels.
军队被调来镇压反叛者。
The Governor has now called in the National Guard to assist the cleanup operation.
总督已经调动了国民卫队协助清剿行动。
The FBI has been called in to investigate.
联邦调查局奉命进行调查。
Extra police were called in to quell the disturbances.
已调集了增援警力来平定骚乱。
The family of the missing girl has been called in by the police to identify the body.
失踪女孩的家人已被警察叫来认尸。
Forensic experts were called in.
法医专家被请来。
3. call sth in表示“下令收回，召回”：
The car company called many cars back in for repairs.汽车公司把许多汽车召回修理。
They called in a lot of cars.他们召回了很多汽车。
The makers have called in some cars with dangerous faults.
制造商已经要求把某些有大毛病的汽车送回去。
Cars with serious faults have been called in by the manufacturers.
有严重缺陷的汽车已被制造商召回。《牛津高阶英汉双解词典》
The bank has threatened to call in all money lent more than twenty years ago.
银行威胁要收回二十多年前所有借出去的钱。
4. 顺路拜访/参观;顺道走访;
Call in at+地点
Call on +人
He just calls in occasionally.
他只是偶尔过来坐坐。
Oh,Paul,what a pity you didn't call in to see Mrs Brown.
噢,保罗,你没有顺便拜访一下布朗夫人,真遗憾!
Call in on your way home and tell me how the interview went.
在你回家的路上顺路来坐坐，向我谈谈会见的情况。
I called in at my local on the way home.
我回家途中去了我住处附近的酒吧。
I'll call in at the chemist's on my way home.
我回家时顺便要去药店一趟。
I'll call on you in my spare time.
有空我去找你。
I will call on him tomorrow.
我明天将去拜访他.