首先，开门见山式表达主旨，标志词为

Do(Does)/Why/How/When/What/...等一般或者特殊疑问词引导的疑问句：

真题例1：

Anyone watching the autumn sky knows that migrating birds fly in a V formation, but scientists have long debate why. A new study of ibises finds that these big-winged birds carefully position their and sync their flapping, presumably to catch the preceding bird‘s updraft--- and save energy during flight. 

(16-10北美，P3）

真题例2：

The rise of agriculture in the Middle East, nearly 11,000 years ago, was a momentous event in human prehistory. But just how farming spread from there into Europe has been a matter of intense research. A new study of ancient DNA from 5000- year-old skeletons found in a French cave suggests that early farmers entered the European continent by at least two different routes and reveals new details about the social structures and dairying practices of some of their societies.

（17-5北美，P4）

真题例3：

Texas gourd vines unfurl their large, flared blossoms in the dim hours before sunrise. Until they close at noon, their yellow petals and mild ,squashy aroma attract bees that gather nectar and shuttle pollen from flower to flower. But “ when you advertise in an open communication network,” says chemical ecologist Ian Baldwin of the Max Planck Institute for Chemical Ecology in Germany. “ You attract not just the good guys, but you also attract the bad guys.” For a Texas gourd plant, striped cucumber beetles are among the very bad guys. They chew up pollen and petals, defecate in the flowers and transmit the dreaded bacterial wilt disease, an infection that can reduce an entire plant to a heap of collapsed tissue in mere days.

 …  …

In one recent study, Nina Theis and Lynn Adler took on the specific problem of the Texas gourd---how to attract enough pollinators but not too many beetles.     

（16.5亚太，P3）

其次，观点反驳式（或观点更新式）表达主旨，即主旨呈现前会有一段文章铺垫，通常在开头段末尾或者后面段落开头进行转折。

真题例1：

The motivation for deep-space travel is shifting from discovery to economics. The

past year has seen a flurry of proposals aimed at bringing celestial riches down to earth. No doubt this will make a few billionaires even wealthier, but we all stand to gain: the mineral bounty and spin-off technologies could enrich us all.

But before the miners start firing up their rockets, we should pause for thought. At first glance…    

（OG1, P5）

真题例2：

When it comes to energy, everyone loves efficiency. Cutting energy waste is one of those goals that both sides of the political divide can agree on, even if they sometimes diverge on how best to get there. Energy efficiency allows us to get more out of our given resources, which is good for the economy and (mostly) good for the environment as well. In an increasingly hot and crowded world, the only sustainable way to live is to get more out of less. Every environmentalist would agree.

But change the conversation to food, and suddenly efficiency doesn't look so good…

（16.5北美，P3）

真题例1：

According to popular belief, within the pupa, the caterpillar’s body is completely overhauled, broken down into a form of soup and rebuilt into a winged adult...It is tempting to think there is no connection between its new life and its old existence as an eating machine.

But not so. A new study has provided strong evidence that the larval and adult stages are not as disparate as they might seem.

… …

（OG1, P5）

真题例2：

The brain is a mutable organ, capable--within limits--of recognizing itself and readapting

To new kinds of sensory input, a phonomenon known as neuroplasticity. It had long been thought that the adult brain was incapable of spawning new neurons --that while learning caused synapses to rearrange themselves and new links between brain cells to form, the brain ‘s basic anatomical structure was more or less static. Maguire’s study suggested the old inherited wisdo was simply not true.

(16.5北美，p5)

【Shaina老师说】：规律不代表一律， 所以有的文章并没有展现上述模式主旨也请不要质疑和惊讶，毕竟阅读路漫漫，有迹可循（哪怕是一点点踪迹），也是很值得欢喜的，想要更多体验，就请亲自读文尝试吧。