事半功倍 [- bàn ɡōnɡ bèi]yield [get] twice the result with half the effort; By doing half the work, one will get double the result.; get twofold results with half the effort; half the work with double results:
•¶ 事情要考虑周详以后再动手, 才能够事半功倍。 Everything must be carefully examined before we act, then twice as much can be accomplished with half the effort.