9. You can't return it, because it's one day past due.
已經過期一天了，因此你不能退貨。
還能這樣說：
You are not allowed to return it, because it has expired for one day.
It is not possible for you to return it, because it has exceeded one day expired date.
應用解析：
in due course 在適當時機；最終
10. I'm sorry we can't exchange it becasue this is our store policy.
對不起不能換，因為這是我們商店的政策。
還能這樣說：
I feel very sorry for that we can't exchange it, because this is not allowed in our store.
I'm sorry our regulation doesn't allow to exchange the goods.
應用解析：
policy-holder 擔保人，保險客戶；
average policy 海損保險單；
policy on sth. （政府、政黨、公司等的）方針，政策
11. Where do I go to return the goods?
我到哪兒退貨呢？
還能這樣說：
Is there any place I can go to return the goods?
Can you show me the place where I can return the goods?
12. We regret that these goods are excluded from the rejection.
很遺憾，此商品不在退貨之列。
還能這樣說：
We are sorry that these goods are not in the list of return commodities.
We regret that these goods are not guaranteed to return.
應用解析：
exclude...from 把……排斥在外；不準進，拒絕
13. The premise of refund for this is that the goods must be in good condition.
退貨的前提是物品得完好無損。
還能這樣說：
The precondition is that the returned merchandise must be safe and sound.
The premise of returning the goods is to make sure it is in perfect condition.