下面句子来自词典和网络，可以参考：用真实条件与否，根据实际情况。语言是灵活的，语法规则要倒装，考试时，没逗号时，倒装不会错的。
Only if you have finished your homework can you go swimming. 除非你把功课做完了,否则不准去游泳.
Only if I get a job will I have enough money to go to school. 我只有找到了工作才有足够的钱上学.
Only if the red light comes on is there any danger to employees. 只要红灯一亮,就表示有危及职工的险情.
" All right -- that'll do. Only if you get married I'll be more lonesomer than ever. "
“ 那好吧 —— 以后告诉就以后告诉吧, 只是你成了家就孤独了我喽. ”
Only if you study hard, you will pass the exam. 只要你努力学习, 就会通过考试.