sine qua non

1. N-SING A sine qua non is something that is essential if you want to achieve a particular thing. 先決條件; 必不可少的事物[正式] ['a' N]

Successful agricultural reform is also a sine qua non of Mexico's modernization. 成功的辳業(yè)改革也是墨西哥實(shí)現(xiàn)現(xiàn)代化的必要條件。