Question

When prices ________, you can go to the store with the lowest price.

1. A.
   is listed
2. B.
   are listed
3. C.
   are made
4. D.
   are used

Answer 1

B
解析：
从句的主语prices是复数，且是动词的承受者，句中谓语需用被动语态，句意为“价格被标出来”，因此C和D中的选项与句意不符，应舍去，而从句的主语为复数形式选项A也被排除。