Although shark attacks can seem vicious and brutal, it’’s important to remember that sharks aren’’t evil creatures constantly on the lookout for humans to attack. They are animals obeying their instincts, like all other animals. Sharks are designed to hunt and eat large amounts of meat. A shark’’s diet consists of other sea creatures — mainly fish, sea turtles, sea lions, and seals. Humans are not on the menu. In fact, humans don’’t provide enough high-fat meat for sharks, which need a lot of energy to power their large, muscular bodies. So why do they attack us In the majority of recorded attacks, the shark bites the victim, hangs on for a few seconds (possibly dragging the victim through the water or under the surface), and then lets go. The shark is simply mistaking a human for something it usually eats. Once the shark gets a taste, it realizes that this isn’’t its usual food, and it lets go. The shark’’s confusion is easier to understand once we start to look at things from the shark’’s point of view. Many attack victims are surfers. A shark swimming below sees a roughly oval shape with arms and legs dangling off, paddling along. This bears a close resemblance to a sea lion (the main prey of great white sharks) or a sea turtle (a common food for tiger sharks). Attacks have also frequently occurred when humans were spear fishing in ocean waters. Sharks are attracted to the signs given off by dying fish — the smell of blood in the water and the electrical impulses given off as the fish struggles. Sharks detect these signals with their ampullae of Lorenzini, a set of "detectors" under the skin on a shark’’s snout (嘴). Once a shark arrives on the scene, it may become agitated and aggressive. There are cases in which sharks seem to attack out of aggression, rather than hunger. Very little is known about shark behavior, but it is believed that some species, including great whites, display dominance behavior over other sharks. This behavior can take the form of "punching" with the snout, or bites that don’’t do much damage to the tough skin of a shark. Unfortunately, when a shark makes a dominance display toward a human, these "gentle" bites can still cause horrendous damage. Sometimes, the cause of a shark attack is the shark is responding to human aggression. Nurse sharks, for example, are generally placid fish that lie still along the bottom of the ocean floor. For some reason, this makes some divers think that it’’s a good idea to pull their tails. Irritated nurse sharks have taught several divers to keep their hands to themselves. In the next section, we’’ll go through a moment-by-moment breakdown of a shark attack. Why the sharks often attack surfers
A. Because of the color of their suits.
Because they have got into the sharks’’ territory.
C. Because they have robbed the sharks of their preys.
D. Because sharks mistake them for its typical prey.
July 21, 2006Dear Sir or Mad .am, Today we have received your bill for 150 engraved crystal vases which you sent us the other day. We had ordered these vases on condition that they should reach us by the end of June. But they arrived here 15 days late. The customers refused to accept the goods because they arrived too late. Since the vases bear their names, we cannot sell them to other customers. So we asked the customers again and again to take the vases, and finally they agreed to accept them, but at a price cut of 30 percent. You may understand how we have lost the customers’ confidence. In this situation, we have to ask you to compensate for the loss we have suffered. We are looking forward to hearing from you as soon as possible. Yours sincerely, George Pastry The purpose of this letter is to ask the supplier to (46) the loss they have suffered. The vases arrived (47) late. The vases could not be sold to the (48) because they have (49) of those who ordered the vases. Therefore, the customers agreed to accept the goods at a price cut of (50) .