I. 完形填空

April 1st is a day on which, in some countries, people try to play tricks on others. If one 　1　 in tricking someone, one laughs and says, "April Fool!" and then the person who is tricked 　2　laughs, too.

One April 1st,a country bus was going along a 　3　 road when it slowed down and stopped. The driver 　4　 turned switches and pressed buttons, but nothing happened.　5　he turned to the passengers with a worried look on his face and said, "This poor bus is getting 　6　.It isn't going as well as it used to.　7　 only one thing to do if we want to get home today. I'll 　8　 three. I want you all to 　9　 forward suddenly as hard as you can. This should 　10　 the bus started again but if it doesn't, I'm afraid there's nothing else I can do. Now, all of you lean back as 　11　 as you can in your seats and get 　12　."

The passengers all pressed back 　13　their seats and waited anxiously.

Then the driver turned to the 　14　and asked, "Are you ready?" The passengers barely had enough 　15　to answer, "Yes."

"One! Two! Three!" counted the driver. The passengers all leant forward 　16　 and the bus started 　17　 at a great speed.

The passengers breathed more 　18　 and began to smile with relief.