Johnny Smith was a good math student at a high school. He loved his computer. He came home early every day, and then he worked with it till midnight. But Johnny was not a good English student, not good at all. He got an F in his English class. One day after school Johnny joined his computer to the computer in his high school office. The school office computer had the grades of all the students: the math grades, the science grades, the grades in arts and music, and the grades in English. He found his English grade. An F! Johnny changed his English grade from an F to A. Johnny' parents looked at his report card. They were very happy.
"An A in English!" said Johnny's Dad. "You're a very clever boy, Johnny."
Johnny is a hacker(黑客). Hackers know how to take information from other computers and put new information in. Using a modem（调制调解器）, they join their computers to other computers secretly. School headmasters and teachers are worried about hackers. So are the police, for some people even take money from bank computer account and put it into their own ones. And they never have to leave home to do it! They are called hackers.
Johnny changed his English grade with the computer in _______.

A．the classroom	B．the school office
C．a bank near his house	D．his own house

When Johnny's parents saw the report, they were happy because _______.

A．Johnny was good at math

B．Johnny loved computers

C．Johnny could join one computer to another

D．they thought Johnny was not poor in English any longer

Who are worried about hackers in the story?

A．Johnny's parents

B．School headmasters, teachers and the police

C．Only the police

D．Many school headmasters and teachers

What should the hackers know well, do you think, after you read this story?

A．Information	B．Bank computer accounts
C．Computers	D．Grades