货币联盟的成员资格只有一个必要标准，即通胀率的集中。

There is only one necessary criterion for membership of a monetary union: convergence of inflation rates.

youdao

设计—建造的竣工—给出竣工达到的必要标准，发放试车证书。

Completion of Design-Build - gives the criteria necessary for completion to be achieved, and for the Commissioning Certificate to be issued.

youdao

这次讨论的主要议题是提高标准的必要性。

The discussion turned on the need to raise standards.

《牛津词典》