This article uses the term government as it is used in Parliamentary systems, i.e. meaning the administration or the cabinet rather than the state.
In first-past-the-post assemblies, where the tendency to gravitate into two major parties or party groupings operates strongly, government and opposition roles can go to the two main groupings serially in alternation.
The more proportionally representative a system, the greater the likelihood of multiple political parties appearing in the parliamentary debating chamber.
Such systems can foster multiple "opposition" parties which may have little in common and minimal desire to form a united bloc opposed to the government of the day.
Some well-organised democracies, dominated long-term by a single faction, reduce their parliamentary opposition to tokenism.