facultative

属于或关于能力的,尤指心智能力的。

Of or relating to faculty, especially to mental faculty.

非强制性的；可选的、自由决定的或选修的。

Not obligate; optional, discretionary or elective.

授予许可或权力做某事的。

That grants permission or power to do something.

能够以不止一种方式执行特定生命功能或生存的。

Able to perform a particular life function, or to live generally, in more than one way.

给定函数为正的(点)。

At which a given function is positive.