Irregular plurals must be memorized.
Here are two matching games. You will match related words. You will work in pairs. Read and follow the directions.
http://www.manythings.org/wbg/irr_plurals1-mw.html
http://www.manythings.org/wbg/irr_plurals2-mw.html
Now look at this website: Word Based Games for ESL Students. There are 29 games. Have a fun time as you learn! Tell your teacher what the best game is.
http://www.manythings.org/wbg/
This will help you build vocabulary.