请问OG   129

129.

      In an effort to reduce their inventories, Italian vintners have cut rices; theri wines have been priced to sell, and they are.

      (A) have been priced to sell, and they are

      (B) are priced to sell, and they have

      (C) are priced to sell, and they do

      (D) are being priced to sell, and have

      (E) had been priced to sell, and they have

       答案是C

       但是我完全看不懂解释，那个they到底指代什么？为什么用do?……劳烦哪位大N解释一下？不胜感激！！

建议楼主收索以前的帖子,已经讨论很充分了.