Is athletic expertise attained or innate Those who have suffered the tongue-lashing of a cruel games master at school might be forgiven for doubting the idea that anyone and everyone is capable of great sporting achievement, if only they would put enough effort into it. Practice may make perfect, but not all are built in ways that make it worth bothering in the first place.
The latest evidence of this truth has been gathered by Sabrina Lee of Simon Fraser University in Vancouver and Stephen Piazza at Pennsylvania State University. They have looked at the physical structure of short-distance runners and found that their feet are built differently from those ofcouch potatoes.
Dr. Lee and Dr. Piazza already knew that short-distance runners tend to have a higher proportion of fast-contracting muscle fibres in their legs than more sedentary folk can muster. They suspected, though, that they would find differences in the bone structure as well. And they did.
The
A. to measure the frequency of the Achilles tendons’ pulling as the feet moved
B. to see how the Achilles tendons slide as the feet moved up and down
C. to compare the sliding motion of the Achilles tendons with the pulling of muscle fibres in the legs
D. to measure the length of the lever of bone that the Achilles tendon pulls on
Space is a dangerous place, not only because of meteors (流星) but also (1) rays from the sun and other stars. The atmosphere again (2) as our protective blanket on earth. Lightgets through, and this is essential for plants to (3) the food which we eat. Heat, too, makes our environment endurable. Various kinds of rays come through the air (4) outer space, but enormous quantities of radiation from the sun are (5) off. As soon as men leave the atmosphere they are (6) to this radiation, but their space suits or the walls of their spacecraft, if they are inside, (7) prevent a lot of radiation damage. (8) is the greatest known danger to explorers in space. The unit of radiation is called "rem". Scientists have (9) to think that a man can (10) far more radiation than 0.1 ram without being damaged: the figure of 60 rems has been agreed on. The trouble is that it is extremely difficult to make (11) about
A. reason
B. it
C. that
D. more
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