What is the function of complement shown in parentheses this sentence Sherry has been a (cook) (waitress) and (receptionist).?

The parentheses in this sentence are used to show alternative words or phrases that could be used in the same place.

In this case, the sentence is describing Sherry's different jobs:

* Cook: This indicates Sherry has worked as a cook.

* Waitress: This indicates Sherry has worked as a waitress.

* Receptionist: This indicates Sherry has worked as a receptionist.

The parentheses imply that Sherry has worked in all three roles at some point.