Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 35.

We're always being urged to stay safe online. But in an era where the internet is part of our everyday lives - for work, fun, study, shopping, even managing finances - it's not always easy to spot the dangers. Web safety expert, Amanda Knox, explores some of the issues lurking in cyberspace.

Her first piece of advice is to install software and a firewall to protect your computer from viruses, hackers and criminals who want to steal your data or financial information. "Think of these as your first line of defense," says Amanda.

So much for protecting yourself against intruders, but what about other problems? Say you've accidentally deleted an important file or you've been at the mercy of a natural disaster. Katy Marsh runs an online photography business from home and when a fire destroyed part of her house it could easily have spelled ruin for her business too. "Luckily I keep a regular back-up of my data so it wasn't a catastrophe."

Whilst most of us are aware of the need to protect our computers, it seems we're more lax when it comes to looking out for ourselves, at least according to a recent web awareness survey. Web safety specialists say better personal awareness is needed and this is due in part to the rise of 'Social Networking' sites like 'Bebo', 'MySpace' and 'Facebook', which allow us to connect with people around the world with similar interests and professional backgrounds.

This brings us to other potential pitfalls. Are the people you meet online who they really claim to be? Can you be sure the person you're chatting with is in fact a 22-year-old Maths undergraduate from London and not someone merely masquerading as a student to win your trust?

When networking and joining online communities it's better to be cautious about the amount of personal information you share. For example, it isn't always necessary to use your real name as a username when registering for a service. You could instead use a pseudonym, or a name that doesn't give away your real identity to other users. And is it really important to tell the world details about your school, college or any local clubs you're a member of?

If you do experience problems from another user be prepared to report them for misusing the service. You'll be doing other users a favour too. And if all else fails, check to see if it is easy to delete your account and leave the service if you choose to and that you have the option to delete all your details.

A general rule of thumb is not to post any information about yourself that you would not be happy for the world to know - not just now but in years to come. This includes photographs of yourself, particularly embarrassing shots of you at that party which you may later regret! It's not always easy to remove information after it's been posted so you - not to mention your future employer - may have an unpleasant surprise a few years down the line.

Câu 31: The effect of the fire was______________.

A food (A) additive is (B) any chemical that food manufactures (C) intentional