一 寸 光 阴 不 可 轻13. M3U1. ReadingFogFog warningWhen Polly left home that morning, the city was already covered in a grey mist. At lunch, the radio forecast that the mist would become a thick fog in the afternoon. At four oclock, Polly left work and stepped out into the fog. She wondered if the buses would still be running.No buses to King Street Once out in the street, she walked quickly towards her usual bus stop.How far are you going? the bus conductor asked her before he took her fare.King Street, said Polly.Sorry, Miss, replied the man, the truth is that it is too foggy for the bus to run that far. Take the Underground to Green Park. The weather might be better there and you might be able to get a taxi.A tall manAs Polly observed the passengers on the train, she had a feeling that she was being watched by a tall man in a dark overcoat. At last the train arrived at Green Park station. While the rest of the passengers were getting out, she glanced at the faces around her. The tall man was nowhere to be seen.FootstepsWhen Polly got to the station entrance, it was empty. Outside, wherever she looked the fog lay like a thick, grey cloud. There was no one in sight. Polly set off towards Park Street. As she walked along the narrow street, she heard the sound of footsteps approaching, but by the time she reached the corner of the street, the footsteps were gone. Suddenly Polly felt a rough hand brush her cheek, and she heard a mans voice in her ear saying Sorry. The man moved away. She could feel her heart beating with fear.The helpful strangerThen she heard the sound again - soft footsteps behind her. A minute before, she had wished for someone to come along. Now she wanted to run, but fear held her still. The footsteps seemed close now. Then a mans voice came out of the darkness. Is anybody there?Polly hesitated. At last she answered, Hello, I think Im lost.A few seconds later, a hand reached out and grasped her arm. Polly found herself staring up at the face of an old man with a beard.Maybe I can help you. Which road do you want? He asked.I live at 86 King Street, Poly replied.Just take my hand, said the man. Come with me. Youll be all right. He took Pollys hand. Watch out for the step here.In his other hand the man carried a stick. Polly heard it hit the step. I can remember some terrible fogs, but maybe that was before your time. I cant see your face, but you sound young. How old are you?Just twenty, answered Polly.Ah, twenty! A nice age to be! I was young once. Now were at the crossroads. Turn left here.Im quite lost now. Are you sure you know the way? Polly was beginning to feel frightened again.Of course. You really shouldnt feel anxious. He held her hand more firmly.The grateful helperHere we are. King Street. He stopped.Thank you so much for coming to my aid, said Polly in relief. Would you like to come in and rest for a while?Its very nice of you, said the man, but Ill be off. There may be more people lost today, and Id like to help them. You see, a fog this bad is rare. It gives me the chance to pay back the help that people give me when its sunny. A blind person like me cant get across the road without help, except in a fog like this.14. M3U1. Project (1)Shark attacksThere are nearly 400 different types of sharks, but only about 30 types are known to have attacked human beings. Many people know that the most dangerous shark is the great white shark, mainly because they have seen the movie Jaws. However, two other sharks are also rather dangerous: the tiger shark and the bull shark.Contrary to what many people might assume, evidence shows that sharks seldom attack humans. There are three types of shark attacks. In the main type, the shark attacks you because it mistakes you for a fish, but when it tastes human flesh it decides to give up and swim away. In the second type, the shark pushes you with its nose to find out if you are fit to be eaten, and then bites you if it thinks you are. In the third type, the shark waits for you to swim by, and then attacks you suddenly. The last two types of attack more often result in the death of humans.To reduce the risk of a shark attack, you should follow these suggestions.n Do not swim in the dark. Sharks can still see you but you cannot see them.n Do not go swimming in the ocean if you have a fresh wound. Sharks can smell blood over a long distance.n Do not wear bright clothing or jewellery, because sharks are attracted to the flash of colors and bright objects.n Stay in groups, as sharks usually avoid large numbers of people. Recently, shark attacks have been increasing as water sports are becoming more popular. If a shark attacks you, follow the advice below. n Keep calm. Do not panic.n Hit the shark on the nose with your fist.n Stick your finger in the sha