凌晨 12 点是谁敲门？
Sam wanted to sleep, so he went to bed. When he was in bed, he heard the doorbell ringing. He had to turn on his lamp. He looked at the clock and it was twelve o’clock. Who would come at such time? He put on his overcoat and went to open the door. When the door was opened, he found no one there. That’s so strange! Then he went back to his bedroom and took off his overcoat. He got back to his bed and turned off the lamp. He decided to go to sleep.
However, he heard the doorbell ringing again! Sam got up quickly and ran to the door. He opened the door again. There was still nobody outside the door. He closed the door and became scared. Then he found a piece of paper on the floor. He picked it up and saw some words: Happy April Fools' Day!
Sam knew it was a prank. He went to his bed and had a good dream. The doorbell didn’t ring again.1.When did Sam go to bed?
A After 20 o’clock.
B Before 11 o’clock.
C Before 12 o’clock.
D After 12 o’clock.
解析：选C。细节理解题。根据第一段He looked at the clock and it was twelve o’clock.可知门铃响时已经十二点了，山姆在12点前就上床睡觉了，故选C。
2.Why did Sam rush to the door when he heard the bell ringing again?
A He was waiting for his friend.
B He was afraid of doorbell’s ringing
C He wanted to find out who the visitor was.
D He wanted to open the door for the visitor.
解析：选C。推理判断题。根据第二段Sam got up quickly and ran to the door. He opened the door again. There was still nobody outside the door.可知山姆想看看门外是谁，故选C。
3.What did Sam found on the floor?
A A doll.
B A lamp.
C An overcoat.
D A piece of paper.
解析：选D。细节理解题。根据第二段Then he found a piece of paper on the floor.可知他在地板上发现了一张纸，故选D。
4.What’s the Chinese meaning of the underlined word “prank”?
A 白纸.
B 信封.
C 彩排.
D 恶作剧.
解析：选D。词义猜测题。根据第二段 Happy April Fools'Day!可知“恶作剧”更符合原文，故选 D。
5.How many times did Sam open the door?
A Once.
B Twice.
C Three times.
D Four times.
解析：选B。细节理解题。根据第一、二段可知门铃一共响了两次，Sam去开了两次门，故选B。