Follow the practice of explicitly stating when a specific sequence within such a group of steps is mandatory.

当在这样一组步骤的特定顺序被托管时，请习惯于跟随明确的状态。

youdao

This mapping is the common practice, but it is not mandatory, though.

这种映射是常见的使用方式，但不是必要的。

youdao

As is proved in practice, the traditional mandatory environmental administrative management can not well meet the practical demand of environmental protection nowadays.

实践证明传统的强制性环境行政管理手段不能完全适应当今环境保护的现实需要。

youdao

But there are many arguments over whether the practice is mandatory or just recommended.

ECONOMIST: Hair, beards and power

Of these three, only Enrolled Agents have been subject to the direct oversight of the IRS Office of Professional Responsibility as to their return preparation practice, testing and mandatory Continuing Professional Education (CPE).

FORBES: Who's preparing your tax return?