"he was the curiousest man about always betting on anything that turned up you ever see, if he could get anybody to bet on the other side; and if he couldn't change sides"
what does this mean in standard american english? plz

It means that the person was a gambler.

Explanation:

The line belongs to The Notorious Frog of Calaveras County, a short story written by Mark Twain. It narrates the story of a guy that narrates another story (called a frame story) about a guy that used to bet on everything. The person described in the story takes his actions (betting) to a point where he puts his money on a frog that had been manipulated before the bet. With this phrase, the speaker wants to express that the guy was totally a gambler.

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)

idk

explanation: