首先，国外似乎对超市更习惯称之为：grocery store，而不是super market。
走廊，走道 aisle。
第一句：请店员找东西时
Where can I find something?
You can go to aisle one.

第二句：不确定东西是否有卖
Just wondering, do you sell something by any chance.
处方药：over-the-counter-drug
乳制品：dairy

第三句：货架上没有，询问是否还有库存
Do you have something in the back ?
Do you have this brand of yogurt in the back.

第四句：不确定商品价格
Can you do a price check for me ?