Fiction vs. Non-Fiction

I once observed Kindergarten students taking a district text. One of the questions that was asked was if the story they have just read was a fiction or non-fiction book. Before the student answered, the teacher had to first explain what each term meant. This caught me off guard because the test was asking for something the students haven't learned yet. Because the teacher explained what each genre meant, most students were able to answer the question correctly. After the test, we were required to ask students if a story was fiction or non-fiction during the guided reading groups.
To introduce fiction and non-fiction stories, I would have the students investigate the differences betweeen a fiction book and a non-fiction book (about the same topic, if possible). What does one book have that the other doesn't? To benefit ELL students, I would make a class T chart and give them their own copy (T chart G.O) so that we could write down the differences together. I think this would be the simplest way to do it. In order for ELL students to understand the graphic organizer concept, I would need to model first, model again but having the students remind me of what I should do, and then allow them to do it on their own. This is not a one day lesson however. I would repeat his process with fiction and non-fiction and then later on with other genres.