As your best friend I will help you all the time you make progress.A. ifB. whenC. unless

问题补充：

As your best friend, I will help you all the time you make progress.

A. if

B. when

C. unless

D. though

答案：

A. if

B. when

(答案→)C. unless

D. though

解析：连词unless意为“除非……如果不……”，“除了……”，多引导一个否定意义的真实条件句，有时也可引导非真实条件旬。