2016-2017学年北京市东城区高二下学期期末考试英语试题

makes more of us being exposed to the risk. We are also developing far more effective methods of recording such attacks, which may have not been reported in the past－and, maybe most important, we are gaining a greater understanding of why run-ins with sharks, though infrequent, occur in the first place.

Some researchers considered shark attacks on humans as misdirected feeding attempts. That is, a shark takes a bite or two out of humans because they look like food. It is thought that especially in shallower waters near shore, where smaller species of sharks may go to feed on schools of smaller fish, many shark attacks occur out of confusion. The shark, born to catch anything looking slightly like a fish may bite a human.

However, according to the most recent report published by Pacific Shark Research Center, the image of surfers, arms reaching out of their boards, being seen as seals (海豹) from below by sharks has largely been discarded, because sharks have extremely powerful vision and are unlikely to mistake a surfer for a seal. Certainly, most attacks have not shown the hunting techniques employed when sharks are in the mood for seals.

Considering the force with which these creatures are capable of attacking, the report provides fresh evidence from survivors of attacks suggesting that the sharks are simply curious. Their mouths function as finely tuned sensory organs, leading sharks to “mouth” unfamiliar objects as a means of examining them and determining their possible food value. So, at worst, these attacks likely result from sharks’ actively assessing whether it’s worth eating a human, not actually trying to eat one.

The researchers contributing to the report also connect shark attacks on humans to the sense of habitat protection. The system is simple: the largest sharks get the best hunting spots. New comers are not welcome, and so forced to leave, violently if necessary. Some shark attacks may be a result of the shark’s natural action to defend its food source against all comers.

Whatever the real cause of shark attacks, we are a far greater threat to them than they are to us. We have decreased their populations, with some 100 million taken each year both on purpose and by accident.

51. Why are media reports on shark attacks increasing? A. More people love taking risks. B. Sharks have a larger population.