我们开车横穿整个城市，结果白跑一趟；商店关门了。

We drove across town ___for ___nothing; the store was closed.

我白等了两个小时。他根本没出现。

I waited for two hours ___for ___nothing. He never showed up.

当项目被取消时，所有的辛勤工作都白费了。

All that hard work went ___for ___nothing when the project was canceled.