21、Mr. King was the manager（经理）of a hotel．One weekend all the hotel in the city were full because there was a large meeting．On Friday night，three men came into the hotel and asked for rooms．Mr. King said there were no rooms ready because of the meeting．The men were unhappy．

Mr. King wanted to help them．He remembered that Room 418，a very small room，was empty．He asked them if they would share a room．The three men said they would．Mr. King said the room would be thirty dollars：ten for each one．Each man gave the money and then went up to the room．

Mr. King Soon began to feel sorry．“Thirty dollars is a lotto ask as price for that small room．” He thought．He called his assistant over and said，“Here is five dollars．Take it to the men in Room 418．I asked too much for their room．”

The assistant took the money．While he was on the way there，he started to think，“How can three men divide five dollars? I'll give them each only one dollar and keep the two dollars for myself．The men will be happy to get something back，and Mr. King will never know．” So the assistant returned one dollar to each man．

Each man had at first paid ten dollars．After the assistant returned them one dollar each，each had paid nine．There were three men，$9×3=$27．The assistant kept $2．$27+$2=$29．Where is the missing dollar?

1．The three men were not happy because _________．

A．there was a large meeting                          B．it was weekend

C．there was only one small room                   D．they wouldn't have a place to stay

2．With the help of the manager，the three men _________．

A．went to another hotel

B．each got a small room for the night

C．stayed together in a small room

D．got a small room Mr. King kept for himself

3．At first，_________．

A．$27 was paid by the three men                   B．$30 was paid by each of the three

C．$25 was paid by the three men                 D．$10 was paid by each of the three

4．The assistant _________．

A．helped the men to divide the money

B．kept two dollars for himself

C．returned three to the men and two to the manager

D．kept three dollars for himself

5．Where is the missing dollar?

A．there wasn't any missing dollar                  B．It was taken by the assistant，too

C．It was taken by Mr. King                      D．It was taken by the three men