draw a line in the sand

• 徒劳无功

draw a line in the sand的用法和样例：

例句

1. It was the cold of his errand, a foot's errand.
   这是因为这趟奔走肯定徒劳无功而感到发冷吧。
2. We wasted all day on a wild-goose chase.
   我们徒劳无功的浪费了一整天。