A requirement is a quality or qualification that you must have in order to be allowed to do something or to be suitable for something. [usu with supp]要求;需求;必要条件；
Its products met all legal requirements…
它的产品符合所有的法律要求。
Graduate status is the minimum requirement for entry to the teaching profession…
研究生学历是从事教学工作的最低要求。
I knew that concentration was the first requirement for learning.
我知道专心致志是学习的首要条件。