Mr. Lee was in bed and was trying to go to sleep when he heard the bell ring. He turned on the light and looked at his clock. It was twelve o'clock. "Who can it be at this time of night?” He thought. He decided to go and find out. So he got up, put on his dressing gown(长袍) and went to the door. When he opened the door, there was nobody there. "That is very strange." Then he went back to his bedroom, took off his dressing gown, got back into bed, turned off the light and tried to go to sleep.
A few minutes later he heard the bell ring again. Mr. Lee jumped out of bed very quickly and rushed to the door. He opened it, but again he found no one there. He closed the door and tried not to feel angry. Then he saw a piece of paper on the floor. He picked it up. There were some words on it: “It is now after midnight, so it is April Fool's Day. April fool to you!”
“Oh, it was the English boy next door!" Mr. Lee exclaimed (惊叫) and almost smiled. He went back to bed and fell asleep at once. The bell did not ring again.
When did Mr. Lee go to bed? He went to bed__________.

A．before twelve o'clock

B．when the bell rang

C．when he saw the boy

D．after twelve o'clock

From this passage, we learn that we can _________on April Fool’s Day.

A．dance and sing at night

B．send presents to children

C．play tricks on others

D．give others a piece of paper

How many times did the bell ring?

A．One

B．Two

C．Three

D．Four