I think you should work harder you are satisfied with the way things are.A. if B. whenC.

问题补充：

I think you should work harder you are satisfied with the way things are.

A. if

B. when

C. since

D. unless

答案：

A. if

B. when

C. since

(答案→)D. unless

解析：选D考查状语从句。句意：我认为你应该更努力地工作，除非你对现状满意。根据句意可知，此处用unless引导条件状语从句。unless“除非，除非在……情况下”。