专业四级是针对英语专业同学的重要考试，其真题的参考价值无可比拟，希望同学们能够吃透真题，通过专四。
Hello everybody. Thank you very much for inviting me here. It's very pleasant to have a chance to talk to you about something that is obviously very much on everybody's minds. I want to talk about an area of security or safety — bicycles. I know a lot of you have bikes. First, when you get your bike, whether it's new or second hand, bring it as soon as possible to us. There will be able to stamp it with a serial number. We actually stamp it into the metal. We'll register the number, put it on our list. This can frighten criminals away if they realize there is a number stamped on it. Second, make sure you buy a good lock. It can be expensive. But it's never a waste of money. If you have an expensive bike, it's worth buying two locks. Do spend money on the good lock, because the cheap ones can be very very easy to cut. Also, make sure you lock the bike to something permanent, though do be considerate to pedestrians. And if the worst happens — you lose your bike. You should immediately report it to the police station calling the serial number that should been stamped.