13. Our price is set according to the quantity.
我們根據數量定價。
還能這樣說：
Our products are priced according to the quantity.
Our price is depending on quantity.
應用解析：
a quantity of 一些；
in large quantities 大量地，大批地
14. The price of our products is unified all over the country.
我們產品的價格是全國統一的。
還能這樣說：
Our products are in the same price around the country.
Our products are set at the same price.
15. How do you sell the watermelons?
西瓜怎么賣？
還能這樣說：
What price do you charge for the watermelons?
How much is the watermelon per half kilo?
諺語：
Cry up wine and sell vinegar.
掛羊頭，賣狗肉。
16. Is there something cheap of this kind?
這一款有便宜的貨沒？
還能這樣說：
Do you have any cheaper ones of this kind?
Is there something of this kind at a lower price?
17. The expensive goods are not all in good quality.
貴的商品質量不見得好。
還能這樣說：
Not all the goods at a higher price have good quality.
Not all the dear goods' quality is fine.
應用解析：
have quality 質量好；
excellent quality 品質優良