If you don’t learn to think you are young you may never learn.A. whenB. whereC. whatD. w

问题补充：

If you don’t learn to think you are young, you may never learn.

A. when

B. where

C. what

D. which

答案：

(答案→)A. when

B. where

C. what

D. which

解析：句意：如果你年轻的时候，不学习思考，你可能永远不会学习。这里用when当…时候，where“在…地方”，what“什么”，which“哪个”，所以选A。