?了如指掌

at one's fingertips了如指掌 Mum is always as busy as a bee in the moring.妈妈每天早上都忙得不可开交。

?在手头

... staff appraisal 员工评估 at one's fingertips 在手头，目前 lodge and accommodation 膳宿 ...

?洞若观火

... you are carrying your joke too far.你打趣开患上太甚度了。 at one's fingertips洞若观火 kill time丁宁时间 ...

?近在手边

... at (one's) command可自由使用（或支配） at one's fingertips近在手边；随时可供应；立即可以得到；精通，熟悉 at one's last gasp临终，于奄奄一息时；在最后时刻；筋疲力尽的 ...