“立竿见影”，汉语成语，意思是在阳光下竖起竹竿，立刻就看到了竹竿的影子（erect/set up a pole and see its shadow）。比喻行事能马上看到效果或付出能马上得到收获。可以翻译为“produce an immediate effect，get instant/quick results”。

例句：

这些投资者觉得收益必须立竿见影。

These investors feel the need to make quick profits.

电视广告宣传活动对他的销售额的影响立竿见影。

The television campaign gave his sales an immediate fillip.