What effect does sentence length have on the overall meaning of the
passage?

taking into account that a theme is the central topic a text treats and can be developed through a story, play, poem etc. the following are themes that can be further developed:  

my best friend jeffrey has many unusual interests. (the story could be about each of the unususal interests)

once a man gives his soul over to evil, he can never go back. (this could be a saying or a proverb)

the three sheepdogs lay around the yard all day. (it could be developed detailing how each of these sheepdogs lay around)

a priest's collar has an unusual effect upon people. (it could be developed detailing the different effect upon people)

innocence is a powerful force in a world full of corruption. (it could be developed detailing how is a world full of corruption)

king lear is a play shakespeare wrote later. (it is just a sentence and doesnt give any idea or topic to be discussed in details.

evil often wears the disguise of innocence. (this could be a saying or a proverb)

the answer is a hoped this

the teacher i would like to have must be a kind, caring and understandable teacher. she should be interactive with us and always plan fun activities to in our studies. she should be a teacher who would correct our mistakes when we do something wrong and guide us if we are weak. she should always be strict if we do something bad but must be praising us when we do something good. she she not take any as her favorite in her class but take everyone as her favorite.

(i hope this will u if there is something send me a reply)