One day a teacher was giving her young students a lesson on how the government works ．She was trying to explain the principle of income tax （收入税）．
“You see ,” she began , speaking slowly and carefully , “each person who works must pay part of his or her salary （薪水）to the government ．If you make a high salary , your taxes are high ．If you don’t make much money, your taxes are low ．”
“Is that clear ?” she asked ．“Does everyone understand the meaning of income tax ?” The students nodded．“Are there any questions ?” she asked ．The students shook their heads ．
“Very good !” she said ．“Now ,I would like you to take a piece of paper and write a short paragraph on the subject of income tax ．”
Little Joey was a slow learner ．He had lots of problems with spelling and grammar , but this time he at least seemed to understand the task ．He took his pen and after a few minutes , he handed the teacher the following composition :
Once I had a dog．His name was Tax．
I opened the door and in come Tax．
The teacher was trying to explain         one day ．

A．the basic principles of the income tax

B．how the government works

C．everyone should pay income tax

D．how much tax one should pay for his income

After the teacher’s explanation,         ．

A．all the students shook their heads

B．many of the students were still puzzled

C．not all the students understood the meaning of income tax

D．a few students disagreed with their teacher

The students were asked         ．

A．to say something about income tax

B．to answer some questions on income tax

C．to write a composition on “income tax”

D．to explain the principle of income tax

Little Joey         ．

A．was clever

B．understood what the teacher said

C．was not clever enough

D．did as what he was told to do