683.One _____ five will have the chance to join in the game.

A.within

B.among

C.in

D.from

684.______ you told me，I had heard nothing of what happened.

A.Till

B.Until

C.After

D.Since

683.答案是C;

考查习惯 搭配:one in/out of five五分之一。

684.答案是B;

till和until通常可通用，但位于句首习惯用until。