Please study the following examples:
If we put a personal pronoun between “非…不可 (fēi ... bù kě),” it indicate that only that person can do the thing that referred in sentence.
Zhè gè gōngzuò fēi nǐ bù kě.
这个工作非你不可。
This work can only be finished by you.
If we put a verb between “非…不可 (fēi ... bù kě),” and put a personal pronoun before it,  it indicates that someone. has to do something. 
Zhè gè gōngzuò nǐ fēi zuò bù kě.
这个工作你非做不可。
You have to do this work.