(used in combination with 才[cai2]) it is only if ... (that one can ...) (as in 只有通過治療才能痊愈|只有通过治疗才能痊愈[zhi3you3 tong1guo4 zhi4liao2 cai2 neng2 quan2yu4] "the only way to cure it is with therapy")
it is only (someone) who ... (as in 只有男性才有此需要[zhi3you3 nan2xing4 cai2 you3 ci3 xu1yao4] "only men would have such a requirement")
(used to express lack of alternatives) can only; have no choice but to (as in 只有屈服[zhi3you3 qu1fu2] "the only thing you can do is give in")