题目内容：

Learning to Run

An article published in the scientific journal Nature discusses an important aspect of human evolution. According to Bramble and Lieberman, Professors at the University of Utah, humans possess a number of features that make them surprisingly good runners. “We are confident that the selection for running was important in the origin of the human body form,” says Bramble.

Traditional thinking has been that humans are poor runners compared to such animals as horses. However, this is only true if we consider running at high speed, especially over short distances. Even an athlete can hardly run as quickly as a horse does, and can only keep up a top speed for 15 seconds or so. But when it comes to long-distance running, humans will do astonishingly well. They can keep a steady pace for many kilometres, and their speed is at least at the same level with that of horses.

Bramble and Lieberman examined 26 parts of human bodies. One of the most interesting of these is the nuchal ligament (韧带). When we run, it is this ligament that prevents our head from moving back and forth or from side to side. Therefore, we are able to run with steady heads, held high. Then there are Achilles tendons at the backs of our legs, forming the mechanical links between the muscles to the bones. They act like strong strings and help to push us forward when we run. Besides, we have low, wide shoulders, a development which allows us to run more effectively. Add to this our light forearms, which swing in co-operation with the movement of our legs to assist balance, and one begins to appreciate the point that Bramble and Lieberman are trying to make.

But what advantage is gained from being good long-distance runners? One theory is that this ability may have permitted early humans to obtain food more effectively. Some scientists guess that early humans may have run after animals for great distances to make them tired before killing them. Running would also have shown another advantage: early humans might have eaten the meat left over from a kill by other large animals. They may have been warned of the existence of a freshly killed animal by vultures (秃鹰), and the faster they got to the scene of the kill, the better.

 “Research on the history of human ability of running has traditionally been controversial,” says Lieberman. “At the very least, I hope this theory will make many people have second thoughts about how humans learned to run and why we are built the way we are.”

1.In Paragraph 2, the author mainly tells us that             .

A. humans are poor runners compared to horses

B. humans are good runners over long distances

C. humans may run at high speed for a short time

D. humans can keep a constant pace when running

2.We can learn from Paragraph 3 that             .

A. tendons are a successful adaptation for running

B. strong muscles and bones keep running effective

C. the shape of shoulders affects the position of heads

D. humans can run faster if they have longer forearms

3.What conclusion is drawn about early humans?

A. They followed birds to avoid danger.

B. They were unable to kill large animals.

C. They developed their big brains for running.

D. They evolved running due to the need for hunting.

4.What does Lieberman mean by saying the underlined sentence?

A. Proving that humans run in a comfortable position.

B. Informing people of the reasons why humans may run.

C. Expressing appreciation of the theory of human evolution.

D. Making people reconsider the idea about our body structure.