（拉）必要条件；要素
双语例句
1.Thus,whatever medical humanities is,it’s not a sine qua non for professionalformation.
所以,无论医学人文是什么,它并不是往医学专业发展的必要条件.
2.Medvedev is also a child of the Putin system,a condition sine qua non for hisnomination.
梅德韦捷夫是普京体系之子,这是他获得任命的必要条件.