mary花了30美元买下了这条牛仔裤.This pair of jeans____ mary 30 dollars.=Mary ____ 30 dollars on this pair of jeans.

问题描述:

mary花了30美元买下了这条牛仔裤.This pair of jeans____ mary 30 dollars.
=Mary ____ 30 dollars on this pair of jeans.

cost
spent
都是过去时