spend后面加介词on或in，spend中文意思是v. 度过，花（时间）花（钱），花费消耗，用尽（精力等）

I spend at least six hours a week in marking.我每周至少要花六个小时批改作业。

They spend hours feeding on the ocean floor.它们花几个小时在海底进食。

Why can't you spend a few bucks on a coat?