Mr. Smith can run very fast. And __1___ is very proud of this.

One day a __2___ breaks into（破门而入） his ___3___ and steals something. Just as the thief is going to run away, Mr. Smith finds him, and quickly ___4___ after him.

“Hey! Stop! Don’t you know you can’t run __5___ than me?” Mr. Smith shouts.

But the thief just doesn’t ___6__. Mr Smith gets very __7____. He tries his best to run faster. Soon he catches up ___8___ the thief and runs ahead of （在。。。的前面） him.

“Why are you in such a hurry?” a __9__ asks.

“I’m trying to catch the thief.” says Mr. Smith.

“But __10___ is the thief?”

At that time, Mr. Smith finds he can’t see the thief any more.