lt will be c___to your friend that you that have pushed the coin through the hole in the paper

It will be （clear清楚的） to your friend that you have pushed the coin through the hole in the paper!
这要结合上下文来填的啊.
Many people like to play tricks.Here is one.It will make your classmates laugh.And it is easy,too.For this trick you need a five-fen coin and a piece of paper.On the paper draw a circle smaller than the coin.Then cut out the little circle you drew just now.
Now give the paper and coin to one of your friends.Ask him or her to push through the hole but do not get the paper broken.Of course he or she can't do it.
Then ask your friend to give you back the paper and the coin,and tell him that you will show him how to do the trick.Put your finger through the hole and push the coin with your finger.It will be clear to your friend that you have pushed the coin through the hole in the paper!
前面解释了怎么做,所以你的朋友会清楚是怎么完成的.
清楚,填clear