On 29 May last year, I was doing my swim training for a half Ironman race in the bay near my home.

    I was finishing my first loop (圈) when I felt jaws coming around my body and a sharp pain. The water was dark, so I couldn't see anything. It just came out of nowhere and then it was gone in a flash. I knew it was something really big and assumed it was a shark. I panicked, but knew I needed to get out of the water. I was kicking wildly in case it came back. There was a lifeguard boat close by, so I waved my arms in the air and screamed for help. It got to me within 20 seconds. At that point I didn't feel anything; adrenaline (肾上腺素) had taken over. The lifeguards held me under the arms and pulled me up out of the water. Then the pain kicked in and it was pretty hard to bear. Some muscle had been bitten off my right arm. I felt a lot of warm, gushing blood.

    My chest felt heavy, as if someone had put their foot on it, and I was having trouble breathing. It was extremely painful. When I got to the hospital, I told the nurses to put me to sleep because of the pain. I just wanted them to fix me.

    I woke up after surgery four hours later. My doctor was amazed when I managed to move my fingers: the bite just missed a major nerve. My right lung had been damaged; I had several broken bones and a nerve in my leg was cut, so I have reduced feeling at the top of my leg. The shark also bit through my upper back muscle.

    Local experts determined that the shark was probably 9-10 feet long. It was young, about seven years old. It just attacked me, left and didn't come back because it figured I wasn't food.

根据短文内容，选择最佳答案，并将选定答案的字母标号填在题前括号内。

A typical school day in the UK starts around 8:30 am. This is often even earlier elsewhere in the world, with students sitting down to their first lesson at 7:30 am in the US. The average teenager ideally needs eight to nine hours' sleep each night, but in reality a lot of teenagers struggle to get this much. A lot of the problems arise because our sleep patterns are not fixed, and they change as we grow.

So a later school start time could help to solve this problem, by ensuring to get their eight plus hours of sleep and react properly to their body's natural rhythms (规律). There has been a general shift over the past 25 years to shorten the school day. This is not at the cost of teaching time (which has remained constant) but at the cost of natural breaks, which has led to reduced lunch time and lesson breaks.

Later start times could help teens' grades and health. This is mainly because it makes the management of children easier. Supervising (监管) hundreds of children “playing” requires effective staffing (人员配备). And there is always the fear that behavior worsens during breaks. So the theory goes that having them in class and strictly supervised must be better.

    But this means that students barely have enough time to absorb what they were doing in maths before suddenly they are thrust into ancient history. And teaching staff also transit from one class to another, with hardly a rest or time to refocus.

    Clearly rethinking the school day could benefit everyone involved. Anyway, it could also lead to better achievement in teenagers and less of a struggle for parents in the mornings. For teachers, it could also mean a less stressful day all around and what could be better than that?

    Movies are a great means of entertainment for many. There are some advantages of watching movies. Comedies, for example, help reduce your blood pressure. Laughter for 15 minutes during a film makes your blood vessels (血管) wider. Besides, when you watch a sad movie, you're more likely to come away from it thinking about loved ones and feeling happy about what you have.

    Watching movies can make you creative. A study shows that young children, who watched the use of magic in Harry Potter, score significantly higher in a creative thinking test than children who watched something else. Moreover, movies are very useful for strengthening people's mental health. They enable people to take time to really relax and temporarily forget about their daily concerns and problems.

    However, watching movies aren't always beneficial. Studies have shown that some people get real pleasure out of being scared by horror movies, but in various ways they may be risking their physical and mental health without even knowing it. When you watch a tense scene in a movie, your heart rate and blood pressure increase. Meanwhile this change in your brain chemistry reminds you of times when you were in a similar state, even if you have no idea you even had those memories. So if something horrible happens to you, being scared again by a movie can unintentionally make you experience it once more.

    Scientists, politicians and parents have debated for decades if being exposed to movie violence leads to actual real-life violence. Overall the answer to that is probably still up in the air, but a new study seems to prove that watching aggression on screen can contribute to being a bully (土霸) in real life, even if it is just in the short term.

    In conclusion, certain movies play a positive role, but not all movies do. It depends completely on the subject of the movie. So it's always advisable to choose the movies concerning something positive.

    We arrived at the hospital to find Dad was very weak, but his smile was as sure as ever. It was another attack of pneumonia (肺炎). My husband and I stayed with him for the weekend but had to return to our jobs on Monday. Local relatives would help Dad get home from the hospital and look after him. But I longed to be able to let him know that we cared too, even when we weren't with him.

    Then I remembered a family tradition when our children were small. When leaving their grandparents' home after a visit, each child would write a love note to their grandparents. They hid notes in the cereal (麦片) box, under a hairbrush, next to the phone or even in the microwave oven (微波炉). For days, their grandparents would smile as they discovered these signs of our love.

    So as I tidied Dad's kitchen and made up a bed for him downstairs in the living room, I wrote some notes. Some were practical, “Dad, I put the food in the fridge so it wouldn't spoil.” Some expressed my love, “Dad, I hope you will sleep well in your new bed.” Most notes were downstairs where he would stay for several weeks until he recovered strength, but one note I hid upstairs under his pillow, “Dad, if you have found this note, you must be feeling better. We are so glad!”

    Just like his medicines strengthened him physically, these “emotional vitamins” would improve his spiritual health. Several weeks later, in one of our regular phone calls, I asked Dad how he was doing. He said, “Pretty good. I just found your note under my pillow upstairs!”

    Scientists have found an unexpected use for virtual reality headsets (耳机). The devices (装置), widely used by computer gamers, show pictures that can be used to test the navigational (导航的) skills of people, who were thought to be at risk of dementia (痴呆). Those who do worse in the tests will be the ones more likely to develop Alzheimer's disease later in life, scientists now believe.

    The discovery that the loss of navigational skills was associated with Alzheimer's was made several years ago by Dennis Chan and his colleagues based at several centers in the UK. These studies used computers to test navigational tasks. But now scientists plan to take their tests to a new level with the use of the virtual reality headsets in which wearers are placed in man-made environments through which they must navigate.

    Around 300 people, aged between 40 and 60, will be arranged to participate in the study. Some will have a gene that puts them at risk of the condition or will come from a family with a history of Alzheimer's. Not all will certainly be affected by the disease, however. Chan's project aims to find out who will. Wearing the headsets, participants will be asked to navigate their way through a series of different environments and then remember the details.

    Researchers recently pointed out the significance of a tiny area of the brain known as the entorhinal cortex (an important memory center in the brain). It acts as a center in a widespread brain network that controls navigation. This now appears to be the first part of the brain that seems to be easily harmed by Alzheimer's.

    The goal of the work is to help people as they develop the disease. "So far, drug trials for Alzheimer's have been applied when people have already got dementia, by which time considerable damage to the brain has already occurred," Chan told the Obsenver. "If we can develop drugs and use them earlier, for example, before the disease has spread beyong the entorhinal cortex, then this would have the potential to prevent the dementia."

    Chinese media and Internet users on Monday decried（谴责）a lack of morals in society after a child was struck twice by two different trucks and left bleeding on the road as more than a dozen bystanders did nothing to help the seriously injured girl.

    The incident, captured by a surveillance camera and aired by Southern Television Guangdong (TVS), showed the two-year-old girl was knocked down and run over by a white truck on a narrow market street on the afternoon of Oct. 13, in Foshan City of Guangdong Province.

    The driver fled the scene of the accident, leaving the girl to bleed on the sidewalk. Over the next six minutes, more than a dozen people walked by the girl, yet not one individual did anything to help her. The girl was then hit a second time by another van before an elderly trash collector came to her aid and brought the attention of the girl's mother, according to the video and eyewitnesses.

    Doctors said that the girl, who was put on life support after being hospitalized, remains in a deep coma. The girl's parents, who are migrants living in the city, are now with her.

    Police said the drivers of both vehicles have been arrested. However, the apathy(冷漠) of the bystanders shown in the video has shocked the public, and people are questioning the morality of society.

    High moral standards were once considered as national pride in China where individuals known for selflessly helping others were adored（崇拜） by the public.

    But in recent years, the perception（观念）of a decline of morals has become a hot topic as profit and materialism are perceived to be affecting society's values.

    On Sept. 2. an 88-year-old man in central China collapsed, his face striking the pavement. Yet, no one came to his aid, and he ended up choking to death on the blood from his nose.

    Some have linked the absence of good Samaritans (模范人物)to a previous case in which a man trying to help an elderly woman who fell was accused of harming her.

    A strong chorus of opinion on the Internet says laws should exempt（免除）Samaritans from liability（责任）, yet laws themselves cannot solve society's morality dilemma.

    Cao Lin, a China Youth Daily commentator, said in a signed article published on Monday that the worry of liability should not be an excuse for not helping, and this case exposes the decline of humanity in Chinese society.