SAT语法模拟练习:揭秘消化

SAT语法大全(附答案)

　　Demystifying Digestion

　　1 What types of food are most easily digested? At first glance, the process by which food fuels our daily activities

　　might seem inexplicable. However, upon closer examination, 2 digestion—the breakdown of food into smaller

　　components to provide the body with necessary nutrients and energy—is a chemical and mechanical process with a

　　consistent sequence of steps.

　　3 Chewing first involves putting food inside the mouth, where the grinding of teeth and secretion of saliva start to

　　break down the physical and chemical composition of food. Once the food has been transformed into 4 a compact

　　mass referred to as a ‘bolus,’ it is swallowed and passes through the esophagus, a muscular tube connecting the

　　throat to the stomach. Although the initial act of swallowing is voluntary, the lower third of the esophagus is made up

　　completely of smooth muscle, over which an individual has no conscious control. This lower third attaches to the

　　stomach—a hollow, muscular organ—which then 5 digest food both by crushing it mechanically

　　and 6 secretes digestive enzymes and other fluids that break down starches and proteins. 7 The contents are then

　　released into the small intestine.

　　Although all organs in the gastrointestinal tract are important for digestion, the majority of nutrient absorption occurs

　　in the small intestine, which is a long, hollow tube arranged into a compressed mass around the center of the

　　abdomen. On the inner surface, this organ is lined with specialized cells arranged into finger-like “villi” and circular

　　“plicae” that facilitate the 8 transfer of important nutrients being transported into the bloodstream. The small intestine

　　is 9 divided into three parts; the duodenum, the jejunum, and the ileum. In the duodenum, digestive juices from the

　　pancreas and gall bladder enter through an opening referred to as the “ampulla of Vater.” These juices break down

　　carbohydrates, lipids, and polypeptides into simpler molecules. The jejunum then links the duodenum to the ileum,

　　which is where the majority of nutrient absorption takes place. 10 Instead, the remaining materials move into the

　　large intestine, where water and salts continue to be absorbed.

　　Once in the bloodstream, nutrients from the digestive tract travel through the cardiovascular network to the liver and

　　then to many different areas of the body. The 11 energy, from cellular division to muscle contraction, contained in

　　these molecules can then be used to activate a number of biological processes. Although we are rarely aware of it,

　　our bodies are constantly at work to provide us with the resources necessary to sustain our lives.

　　1 In order to help make the abstract topic of digestion accessible to a broad audience, the writer wants to introduce it

　　with a specific, commonplace example. Which choice best accomplishes this purpose?

　　A. NO CHANGE

　　B. What role do our digestive organs play in our general physical health?

　　C. What role do our intestines play in the process of digestion?

　　D. How do our bodies extract energy from a peanut butter and jelly sandwich?

　　2

　　A. NO CHANGE

　　B. digestion: the breakdown of food into smaller components, to provide the body with necessary nutrients and

　　energy,

　　C. digestion; the breakdown of food, into smaller components to provide the body with necessary nutrients and

　　energy

　　D. digestion, the breakdown of food—into smaller components to provide the body with necessary nutrients—and

　　energy

　　3 Which choice most effectively helps establish the main topic of the paragraph?

　　A. NO CHANGE

　　B. The process of digestion begins in the mouth, C. Certain chemical reactions occur when people put food in their mouths,

　　D. When they're hungry, people put food in their mouths,

　　4

　　A. NO CHANGE

　　B. a succinct

　　C. a summary

　　D. an abbreviated

　　5

　　A. NO CHANGE

　　B. are digesting

　　C. were digesting

　　D. digests

　　6

　　A. NO CHANGE

　　B. to secrete

　　C. will secrete

　　D. by secreting

　　7 The writer is considering deleting the underlined sentence. Should the writer make this deletion?

　　A. Yes, because the sentence repeats information that has already been stated in the passage’s description of the

　　digestive process.

　　B. Yes, because the sentence interrupts the focus of the paragraph with information that is not directly related to

　　the process of digestion.

　　C. No, because the sentence provides an effective transition to the topic of the next paragraph, which focuses on

　　the small intestine’s role in digestion. D. No, because the sentence provides necessary information about the process of digestion in the esophagus

　　8

　　A. NO CHANGE

　　B. transfer of important nutrients

　　C. transfer of important, crucial nutrients

　　D. transfer into the bloodstream of important nutrients

　　9

　　A. NO CHANGE

　　B. divided into three parts:

　　C. divided: into three parts,

　　D. divided into: three parts,

　　10

　　A. NO CHANGE

　　B. In addition,

　　C. However,

　　D. From there,

　　11

　　A. NO CHANGE

　　B. energy contained in these molecules, from cellular division to muscle contraction, can then be used to activate a

　　number of biological processes.

　　C. energy contained, from cellular division to muscle contraction, can then be used to activate a number of

　　biological processes in these molecules.

　　D. energy contained in these molecules can then be used to activate a number of biological processes, from

　　cellular division to muscle contraction.

　　DABAD DCBBD D

SAT水平能力测试【0元免费测试】