Today I was teaching my students of English conversation name's "The market is closed" but there's something make me feel confused with how to use. There are "close" and "closed" as what's Jeff and Sharon are talking to each other as in the picture below. Who can explain to me of how to use them?. Like when should I use them between the word "close" and "closed" and why?. Usually when I don't understand about English language I like to search on Google for the meaning as in Thai language for explain to my students but today I can't found out about these that which one can make me understand with how to use. So, please. .. I need help.