The structure 除非...，才...
“Unless…”
The structure 除非…，才… 
expresses that some action won't happen unless a certain condition is met.
expresses that some action won't happen unless a certain condition is met.Scheme
除非
condition
才
result
We should state 除非 at the beginning of the sentence. The first subject is stated right after it.
We should state 才 in the second part of the sentence. The second subject is stated before it.
Scheme
除非
subject 1
predicate 1
subject 2
才
predicate 2
Examples
除非他给我增加工资，我才会留下来
I won't stay unless he gives me an increase in pay
chúfēi tā gěi wǒ zēngjiā gōngzī, wǒ cái huì liúxiàlái
除非你跟我同意，我才会跟你一起去
I will go with you only if you agree with me
chúfēi nǐ gēn wǒ tóngyì, wǒ cái huì gēn nǐ yìqǐ qù
除非你们走了，我才可以开始工作
I can't start working until you guys are gone
chúfēi nǐmen zǒu le, wǒ cái kěyǐ kāishǐ gōngzuò