Excuse me ,how much are these postcards?They are for _____ if the cost of o

问题描述:

Excuse me ,how much are these postcards?They are for _____ if the cost of o

大意: 你好,请问这些明信片多少钱?
-他们是为了……, 如果这个成本……
可以填 for free 免费
for sale 待售

填free,for free是免费的

题目不完整呢,不过答案应该是free.for free是指免费的.