越来越多的经验告诉我们，若一个短语的字面意思很奇怪或是不合常理，那么它只能是一种习惯用语了，像之前的 bite the bullet，bite the dust 等等，还有 beck and call，字面意思是“小溪和通话”，没有任何的实际意义，它是一个习惯用语，可以意为“随时待命，唯命是从，俯首帖耳”等，寓意：
being completely available to someone when needed
在需要的时候完全可以被某人利用
to immediately respond when called upon by a particular person
在某人要求时立即作出反应
to make oneself immediately available on the request of another person
应另一个人的要求立即使自己随时待命
ready to perform tasks for someone immediately it is demanded
随时准备为某人执行任务
例如：
No matter what time of day it is, she is always at his beck and call.
不管一天中的什么时候，她总是听候他的吩咐。
Whatever you need, I'll be on your beck and call to provide them.
不管你需要什么，我都会按你的吩咐打电话给你。
解析：此句是 whatever 引导的让步状语从句.
The servants at the palace are at the beck and call of the king and the entire royal family.
皇宫里的仆人听命于国王和整个皇室。
I knew he was trying to wheedle me into being at his beck and call.
我知道这是他拉拢我，好让我俯首贴耳地为他效劳。
With his personal assistant on his beck and call, Adam was able to get a lot of work done in the office today.
有随时待命的私人助理，亚当今天可以在办公室完成许多工作。
解析：be able to do sth 强调通过自己的努力而获得的能力。
其实在很早以前，beck 和 beckon 是同一个单词，所以若把习语变成 beckon and call 就好理解了，虽然跟它的寓意还是有差异，但字面意思“招手示意和呼叫”变得有意义了。
