Passage 1
Title：宇宙大爆炸
主题：天文类话题
文章内容回顾：
主要讲述宇宙起源的两种学说，稳定宇宙和发展宇宙，大爆炸理论。他们之间共同承认膨胀。 难度分析： 天文类话题，在
相关背景内容：
The Big Bang Theory is an American sitcom created by Chuck LorreandBill Prady, both of whom serve as executive producers on the show along with Steven Molaro. All three also serve as head writers. It premiered on CBS on September 24, 2007. The seventh seasonpremiered on September 26, 2013. The show is primarily centered on five characters living in Pasadena, California: roommates Leonard Hofstadter and Sheldon Cooper, both physicists; Penny, a waitress and aspiring actress who lives across the hall; and Leonard and Sheldon's equally geeky and socially awkward friends and co-workers, mechanical engineerHoward Wolowitz and astrophysicist Raj Koothrappali. The geekiness and intellect of the four guys is contrasted for comic effect with Penny's social skills and common sense. Over time, supporting characters have been promoted to starring roles: Leslie Winkle, a physicist colleague at Caltech and, at different times, a lover of both Leonard and Howard; Bernadette Rostenkowski, Howard's girlfriend (later his wife), a microbiologist and former part-time waitress alongside Penny; neuroscientist Amy Farrah Fowler, who joins the group after being matched to Sheldon on a dating website (and later becomes Sheldon's girlfriend), and Stuart Bloom, the cash-strapped owner of the comic book store the characters often visit.
Passage 2
Title：水藻
主题：环境生态学类话题
文章内容回顾：
文章主要讲述了水藻在海中的分布、作用以及影响水藻纵横分布的因素，主要讲一个颜色纵向分布。 难度分析： 环境生态学类话题，文章结构是因果型文章结构，框架结构较为清晰。学生对于这一题材的阅读都较为熟悉，但由于缺乏部分专业词汇，而似的文章总体有一定难度。近期海洋生物类话题正逐渐回归托福阅读考试，值得引起考生的注意。
相关背景内容：
Algae are a very large and diverse group of eukaryotic organisms, ranging from unicellular genera such as Chlorella and thediatomstomulticellular forms such as the giant kelp, a large brown alga that may grow up to 50 meters in length. Most areautotrophic and lack many of the distinct cell and tissue types found in land plantssuch as stomata, xylem and phloem. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, adivision of algae that includes Spirogyra and the stoneworts. There is no generally accepted definition of algae. One definition is that algae "have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells".Other authors exclude all prokaryotes and thus do not consider cyanobacteria (blue-green algae) as algae.
Passage 3
Title：鸟类的集体效应
主题：生物学类素材
文章内容回顾：
文中主要讲述了鸟类的集体效应，他们怎么通过集群来保护自己的子嗣和其他的一些集体行为。
难度分析：
生物学类素材在最近几次托福阅读中是比较常见的素材，考生后续考试中需要注意。其中，关于哺乳动物、鸟类动物为热点话题。
相关背景内容：
A flock is a group of birds conducting flocking behavior in flight, or while foraging. The term is akin to the herd amongst mammals. The benefits of aggregating in flocks are varied and flocks will form explicitly for specific purposes. Flocking also has costs, particularly to socially subordinate birds, which are bullied by more dominant birds; birds may also sacrifice feeding efficiency in a flock in order to gain other benefits.[1] The principal benefits are safety in numbers and increased foraging efficiency. Defense against predators is particularly important in closed habitats such as forests where predation is often byambush and early warning provided by multiple eyes is important, this has led to the development of many mixed-species feeding flocks. These multi-species flocks are usually composed of small numbers of many species, increasing the benefits of numbers but also increasing potential competition for resources. Group size is a major aspect of the social environment of gregarious animals. However, one has to be careful when using group size measures to characterize animal sociality, because average individuals live in groups larger than mean group size.