The Riddle

"Hey, Mom! Do you know this rhyme?" Miles asked from the porch swing. "Here's the church. Here's the steeple. Open the door and see all the people." Miles showed her the hand motions that went along with the words.Mom laughed. "That's an old one, Miles, but I still like it. Come over here. I have a riddle for you."Miles slid off of the porch swing and walked down the steps to where his mother was on her knees, working in the flower bed. She wrote in the dirt with her finger: CH _ _ CH. "Do you know what this is?" she asked.Miles read the letters out loud. "C-H blank blank C-H." He looked at his mom. "That doesn't mean anything at all, does it?""You're right. It doesn't mean anything," said Mom."Aw, Mom," said Miles. "Then it isn't really a riddle.""That is, it means nothing until you put a couple of important letters on those blanks," added Mom. "What do you think they are?You can figure