Answer:
Uhm, write a story! Say something like "I thought it could be a miniature rocket or a few bucks. Maybe it could be a brand new book, or maybe a misshaped Barbie doll. Maybe it could be a prank, like a fake spider, I didn't really know. All I had to do was reach into the bag and pull whatever was in, out." You can continue from there. In the end, you just have to make sure to add a topic sentence and some more examples of what it could be. They can be weird, funny, nice, or whatever. You can do this!!!
