The origin of ____ life on earth is ____ question that interests astronomers.（原创）

The origin of ____ life on earth is ____ question that interests astronomers.（原创

1. A.
   the; the
2. B.
   \; a
3. C.
   \ ; the
4. D.
   the; a

 The origin of ____ life on earth is ____ question that interests astronomers.（原创）

     A. the; the                  B. \; a                         C. \ ; the                     D. the; a

The origin of ____ life on earth is ____ question that interests astronomers.（原创）