11.   The ancient treasures he restores are so precious that the location of his workshop is a carefully guarded secret.

12.   And as is typical in such facilities, the work currently under way is a closely guarded secret.

13.   At the same time, because most shows are produced by privately held companies, souvenir sales figures are closely guarded secrets.

14.   Before then, resources for unusual sinks were closely guarded secrets, Bates says.

15.   Both Vice President Al Gore, the Democratic presidential hopeful, and Bush are keeping the names of potential running mates closely guarded secrets.

16.   A spokesman for the company said the solution to the puzzle has been a closely guarded secret.

17.   According to Yakushkin, Yeltsin kept his decision to resign a closely guarded secret until the last minute.

18.   After correcting obvious mistakes, consumers may have trouble improving a credit score because the computations remain a tightly guarded secret.

19.   But the real numbers remain a closely guarded secret.

20.   China executes more people each year than the rest of the world combined, although the exact number is a tightly guarded state secret.