填空题 You should spend about 20 minutes on Questions 1-13, which are based on Reading Passage 1 below.

Cats Show Perfect Balance Even in Their Lapping

It was known that when cats lap, they extend their tongues straight down towards the bowl with the tip of the tongue curled backwards like a capital 'J' to form a ladle, so that the top surface of the tongue actually touches the liquid first. We know this because another MIT engineer, Dr. Edgerton, who first used strobe lights in photography to stop action, filmed a domestic cat lapping milk in 1940. But recent high-speed videos made by this team clearly revealed that the top surface of the cat's tongue is the only surface to touch the liquid. Cats, unlike dogs, aren't dipping their tongues into the liquid like ladles after all. Instead, the cat's lapping mechanism is far more subtle and elegant. The smooth tip of the tongue barely brushes the surface of the liquid before the cat rapidly draws its tongue back up. As it does so, a column of milk forms between the moving tongue and the liquid's surface. The cat then closes its mouth, pinching off the top of the column for a nice drink, while keeping its chin dry.
The liquid column is created by a delicate balance between gravity, which pulls the liquid back to the bowl, and inertia, which in physics, refers to the tendency of the liquid or any matter, to continue moving in a direction unless another force interferes. The cat instinctively knows just how quickly to lap in order to balance these two forces, and just when to close its mouth. If it waits another fraction of a second, the force of gravity will overtake inertia, causing the column to break, the liquid to fall back into the bowl, and the cat's tongue to come up empty.
While the domestic cat averages about four laps per second, with each lap bringing in about 0.1 millilitres of liquid, the big cats, such as tigers, know to slow down. They naturally lap more slowly to maintain the balance of gravity and inertia.
Roman Stocker of MIT's Department of Civil and Environmental Engineering (CEE), Pedro Reis of CEE and the Department of Mechanical Engineering, Sunghwan Jung of Virginia Tech and Jeffrey Aristoff of Princeton used observational data gathered from high-speed digital videos of domestic cats, including Stocker's family cat, and a range of big cats (a tiger, a lion and a jaguar) from the Boston-area zoos, thanks to a collaboration with Zoo New England's mammal curator John Piazza and assistant curator Pearl Yusuf. And, in what could be a first for a paper published in Science, the researchers also gathered additional data by analysing existing YouTube.com videos of big cats lapping.
With these videos slowed way down, the researchers established the speed of the tongue's movement and the frequency of lapping. Knowing the size and speed of the tongue, the researchers then developed a mathematical model involving the Froude number, a dimensionless number that characterises the ratio between gravity and inertia. For cats of all sizes, that number is almost exactly one, indicating a perfect balance.
To better understand the subtle dynamics of lapping, they also created a robotic version of a cat's tongue that moves up and down over a dish of water, enabling the researchers to systematically explore different aspects of lapping, and ultimately, to identify the mechanism underpinning it. 'The amount of liquid available for the cat to capture each time it closes its mouth depends on the size and speed of the tongue. Our research—the experimental measurements and theoretical predictions—suggests that the cat chooses the speed in order to maximise the amount of liquid ingested per lap,' said Aristoff, a mathematician who studies liquid surfaces. 'This suggests that cats are smarter than many people think, at least when it comes to hydrodynamics.'
Aristoff said the team benefited from the diverse scientific backgrounds of its members: engineering, physics and mathematics. 'In the beginning of the project, we weren't fully confident that fluid mechanics played a role in cat's drinking. But as the project went on, we were surprised and amused by the beauty of the fluid mechanics involved in this system,' said Jung, an engineer whose research focuses on soft bodies, like fish, and the fluids surrounding them.
The work began three-and-a-half years ago when Stocker, who studies the fluid mechanics of the movements of ocean microbes, was watching his cat lap milk. That cat, eight-year-old CuttaCutta, stars in the researchers' best videos and still pictures. And like all movie stars (CuttaCutta means 'stars stars' in an Australian aboriginal language), he likes being waited on. With their cameras trained on CuttaCuttas bowl, Stocker and Reis said they spent hours at the Stocker home waiting on CuttaCutta...to drink. But the wait didn't dampen their enthusiasm for the project, which very appropriately originated from a sense of curiosity.
'Science allows us to look at natural processes with a different eye and to understand how things work, even if that's figuring out how my cat laps his breakfast,' Stocker said. 'It's a job, but also a passion, and this project for me was a high point in teamwork and creativity. We did it without any funding, without any graduate students, without much of the usual apparatus that science is done with nowadays.'
'Our process in this work was typical, archetypal really, of any new scientific study of a natural phenomenon. You begin with an observation and a broad question, "How does the cat drink?" and then try to answer it through careful experimentation and mathematical modeling,' said Reis, a physicist who works on the mechanics of soft solids. 'To us, this study provides further confirmation of how exciting it is to explore the scientific unknown, especially when this unknown is something that's part of our everyday experiences.'

—Science Daily

填空题 Answer the questions below.
Choose NO MORE THAN THREE WORDS from Reading Passage 1 for each answer.
Write your answers in boxes on your answer sheet.

Which two of the physical factors do cats use when they lap milk?

填空题 How much does a domestic cat get back to its mouth when it laps liquid, like milk?

填空题 Where did researchers find out sources in the research that may publish first paper in Science?

填空题 What is the name of the ratio between gravity and inertia?

填空题 In which aspect are cats smarter?

填空题 Do the following statements agree with the information given in Reading Passage 1? In boxes on your answer sheet, write TRUE if the statement agrees with the information FALSE if the statement contradicts the information NOT GIVEN if there is no information on this When cats lap, they curl the tongue like a 'J' so that the top surface of the tongue becomes the only part touching the water.

填空题 Cats' lapping way is more perceptive and elegant than dogs.

填空题 Inertia leads the water column back to the bowl regardless of the disruption of other forces.

填空题 The bigger the cats are, the more slowly they lap the liquid.

填空题 Complete the sentences below.
Choose NO MORE THAN THREE WORDS from Reading Passage 1 for each answer.
Write your answers in boxes 10-13 on your answer sheet.

Inertia is a norm in physics that is related to the ______ of an object.

填空题 Researchers create a ______ of cats for better study of cats' lapping.

填空题 The ______ of cats' tongue is to ensure the maximum amount of water they lap.

填空题 At first, there is some uncertainty of ______, which finally becomes the surprise of the researchers.