问题
选择题
___________you try to do something beyond what you have already mastered, you will never grow.
A.Since
B.When
C.Though
D.Unless
答案
D
题目分析:A.Since 自从,因为,B.When 当…时候,C Though虽然,D.Unless除非,如果不,相当于if not…句意:如果你不努力做超出你已经掌握的东西,你永远不会成长。根据句意选D。