1. Keep it simple! It is only o.k. to use words or phrases they may not know
if you also explain them. Keep the concepts simple too.
Examples: Instead of saying that Jesus "rose (a flower) again", say that He "came back to life." Or replace "shed His blood" with "bled."
2. Do not do any one activity for a long period of time. (And for a preschooler, five minutes can be a long time!)
We generally keep preschool Bible lessons to no more than ten minutes. But you can even make that seem shorter be singing a song or reminding them of their scripture memory verse at appropriate places during the lesson.