She is the best swimmer of the school
Identify the parts of speech in the following sentence.
https://www.englishclub.com/grammar/?from=ec-navbar
and
http://www.chompchomp.com/terms.htm
Start with the verb in the sentence. What is it?
Then identify the subject.
The rest should come fairly easily after you identify those basic parts of the sentence.
Give it a try, and someone will check your work.