题目内容：

It is known to us that computer users are being warned by industry experts to pay attention to secret codes which could be used to record their conversation.

E-mails, screen savers, and electronic greeting cards can carry a secret code which is able to turn on the computer’s microphone, make a recording, and forward it to someone else without the user’s knowledge.

In fact any attachments (附件) sent to a computer, whether it is a game of Space Invaders, or a moving picture, can possibly be used to spy (窥探).

Experts say people should always think twice about opening attachments because --- although not common --- bugging (窃听) by computer can and has been done.

Bill Lyons, head of the Internet Security Company Finjan, said, “People in the army have tested this and you can be sure, if people in general are aware of it, then computer hackers (黑客) are aware of it. The frightening thing is that there are tools on the Internet which people, using a simple search method, can find, and which will enable them to attach this dangerous code to simple attachments.”

1.What is the advice given in the passage?

A. Use secret codes to record other people’s conversation.

B. Be careful when opening an attachment.

C. Never open any attachments.

D. Never use secret codes.

2.What worries the experts is that ___ .

A. nobody seems to believe such things

B. nobody knows the danger of the code

C. tools can easily be used to tie dangerous codes to e-mails

D. effective ways can never be found to deal with the problem.

3.Which of the following is TRUE according to the passage?

A. A moving picture cannot be used to spy.

B. Electronic greeting cards cannot carry a secret code.

C. A secret code is used to destroy the computer system.

D. Any attachments sent to a computer may carry a secret code.