What does "best" sometimes mean in the specification of utility model patent? Thank you.

The manual will give several examples to illustrate the technical scheme, and it is best to refer to a special case.

For example, part A of an article is made of metal.

Generally speaking, the preferred component A can be iron, copper, etc. From general situation to special situation;

Alternatively, component A needs good conductivity, and metals generally have conductivity, but copper is more effective.