今年的STS竞赛，共有超过 2600名学生提交申请，他们来自46个州、华盛顿特区、北马里亚纳群岛、波多黎各以及全球16个国家的826所高中。经过激烈角逐，最终有300位年轻人脱颖而出，入选本届学者名单—— ...

So, that means that we can use 'on the cusp of' with two different complements, and we can also say 'on the cusp between' with two complements. However, we can also just use one complement in a ...