一對非常有趣的句子，值得深思

The mayor was among the people invited.
市長在受邀的人士之中。
"among the people (who were) invited" is a prepositional phrase (adverbial subject complement) telling where the mayor was.

The mayor was invited among the people.
市長在人們之中被邀請了。
"among the people" is a prepositional phrase (adverbial adjunct) telling from where the mayor was invited.

Both sentences are correct but with different meanings.

(1)Someone wanted to invite our mayor among the group.
(2)We(people) invited the mayor.