几个小男孩用石块打水漂。

Small boys were skimming stones across the water.

我站着看他打水漂游戏。

I stood watching him play ducks and drakes.

那几个男孩子用石块往水塘里打水漂。

The boys were skipping stones across the pond.

跟新东方学英语就是把钱打水漂。

To study English with Xindongfang is just pouring money down the drain.