From the word ________ on the old pot, we decide that it dates back to at least five hundred years ago．

1. A.
   having been marked
2. B.
   marked
3. C.
   to be marked
4. D.
   being marked

From the word ________ on the old pot, we decide that it dates back to at least five hundred years ago.

    A. having been marked             B. marked     

C. to be marked                       D. being marked