conjunction followed by conjunctive: 除非chú fēi…才cái…or by
conjunction: 不然bú rán/否则fǒu zé
除非交通阻塞,我才会迟到。
Chú fēi jiāo tōng zǔ sāi,wǒ cái huì chí dào。
I won’t be late unless there is a traffic jam.
除非你每天吃药,不然/否则你的病好不了了。
Chú fēi nǐ měi tiān chī yào,bú rán /fǒu zé nǐ de bìng hǎo bú liáo le。
Unless you take the medicine every day, you won’t get well.
[1] Yip, P. C., Rimmington, D., Xiaoming, Z., & Henson, R. (2009). Basic Chinese: a grammar and workbook. Taylor & Francis.