--- The thread of my kite broke and it flew away．

--- I told you it would easily bread ________ it was the weakest．

1. A.
   when
2. B.
   for
3. C.
   since
4. D.
   where

-- The thread of my kite broke and it flew away. 

-- I had told you it would easily break_______ it was the weakest.            

-- The thread of my kite broke and it flew away. 
-- I had told you it would easily break_______ it was the weakest.