九牛一毛，汉语成语，字面意思是“九头牛身上的一根毛(a single hair out of nine ox hides)”，比喻渺小、轻微，或很大数量中的极少数，与英文习语“a drop in the ocean(bucket)”意思相近，表示“a very small quantity, especially one that is too small;an insignificant contribution toward solving a large problem”。

例句：

许多公司捐赠食品和药品帮助地震幸存者，但和所需之物相比只是九牛一毛。

Many companies donated food and medicine to help the survivors of the earthquake, but it was just a drop in the bucket of what was needed.

同播出的实际开支相比较，他那点酬金不过是九牛一毛。

His fee is a drop in the ocean compared with the real cost of broadcasting.