每日商务英语 第543期:杯水车薪

a drop in the bucket------杯水车薪（成语）

英文释义
(IDIOM) A very small and insufficient amount of something.

例句
When I was a university student the money my family gave me was just a drop in the bucket because my living expenses were so high.
我上大学时生活成本太高，家里给我的钱只是杯水车薪。