-- The thread of my kite broke and it flew away.-- I had told you it would easily break it

问题补充：

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

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

A. when

B. since

C. unless

D. where

答案：

A. when

B. since

C. unless

(答案→)D. where

解析：连词辨析。When当……时候； since自从……以来，由于；unless除非；where在哪儿。句意：我的风筝的线断了，它飞远了。——我告诉过你它非常容易断，那是最薄弱的地方。