综合写作：
While scientists have been seriously observing animal behavior for well over a hundred years, the study of why animals play has only recently become a serious research topic. At least three different theories have been advanced to explain the phenomenon.
The first theory is called the surplus energy theory. This theory maintains that some animals, mammals for example, are so efficient at using energy that they often do not manage to spend all the energy they receive through food. They end up with unused, surplus energy that they cannot store. According to this theory, animals have to play to get rid of the surplus energy that they have not used.
A second theory is called the instinct-practice theory. It states that young animals play as part of their physical education. The physical actions that animals will need to use for survival are instinctual, that is, preprogrammed in their brains. The animals, however, have to train their bodies to be able to perform these actions. So this theory explains why the play of young animals centers on real-life tasks. For example, predatory animals those that hunt, kill, and consume other animals for food have often been observed attacking and biting during play, which are precisely the skills they will need in order to hunt for food.
A third theory, called the social functions theory, is that animals play to establish social relationships within their group. Basically, play gives animals a chance to bond with the other members in their group. For example, in a study of rats, those that played together made high-pitched squeaks that were accompanied by the release of pleasure-causing chemicals in the brain. This association of play with pleasure may motivate the animals to stay together as a harmonious group even while not playing.
听力音频：
听力对应中文字幕：
https://www.bilibili.com/video/BV1VWqPYeEYL?t=4.0
学术写作：
Dr. Achebe
In today’s world, we have various ways to stay informed about current events. Traditional sources like television and newspapers have long been trusted by many, providing detailed and well-researched news. However, with the rise of social media, an increasing number of people are turning to these platforms for quick and accessible updates. Which do you think is a better source of news: traditional outlets like television and newspapers, or social media?
Claire
I believe social media is a better source of news because it provides quick updates. For example, during breaking news events, social media platforms often deliver information faster than traditional outlets like newspapers or television. This immediate access allows people to stay informed in real-time.
Paul
I think traditional news sources are better because they tend to be more accurate. Television, for instance, not only provides well-researched reports but also offers visuals that help viewers understand the story better. Social media might be faster, but it often lacks the depth and verification traditional sources provide.
