有道题选项里面有cut down和knock off.答案选的knock off,为什么不可以用cut down
大概是这样的意思,原句不记得了.
i know you want to buy my mp3.I cost 400 to buy it.
,as it is not new,i'll______20% .用cut down不行吗?难道只能是只砍价,不能指卖家主动少去吗?