单选题
单选题
所谓加权即重点突出某方面的特性。之所以要加权是因为在一般的成像过程中，组织的各方面特性（如：质子密度、T
值、T
值）均对MR信号有贡献，几乎不可能得到仅纯粹反映组织一种特性的MR图像，通过利用成像参数的调整，使图像主要反映组织某方面特性，而尽量抑制组织其他特性对MR信号的影响，这就是"加权"。T加权成像是指这种成像方法重点突出组织纵向弛豫差别，而尽量减少组织其他特性如横向弛豫等对图像的影响；T加权成像重点突出组织的横向弛豫差别；质子密度加权像则主要反映组织的质子含量差别。
关于TWI的叙述正确的是
A:长T的组织呈低信号 B:脂肪呈高信号 C:短T的组织呈低信号 D:脑脊液呈低信号 E:骨骼呈高信号
患者女，57岁。胆总管结石。入院行胆总管切开探查，T型管引流术。
术后针对T型管引流的护理措施，不妥的是
A:记录引流胆汁的量、色及性状 B:每日用生理盐水冲洗T型管 C:一般留置2周 D:拔管前经T管胆道造影 E:拔管前夹管观察1~2天
ε（3-t）ε（t）=（）
A:ε（t）-ε（t-3） B:ε（t） C:ε（t）-ε（3-t） D:ε（3-t）
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.
They looked at seven university sprinters who specialize in the 100-metre dash and five 200-metre specialists, and compared them with 12 non-athletic university students of the same height. In particular, they looked at the sizes of bones of the toes and heel. They also used ultrasonic scanning to measure the sliding motion of the Achilles tendons of their volunteers as their feet moved up and down. This allowed them to study the length of the lever created by the tendon as it pulls on the back of the heel to make the foot flex and push off the ground.
Dr. Lee and Dr. Piazza found that the toes of their short-distance runners averaged 8.2cm in length, while those of common people averaged 7.3cm. The length of the lever of bone that the Achilles tendon pulls on also differed, being a quarter shorter in short-distance runners.
These findings suggest short-distance runners get better contact with the ground by having longer toes. That makes sense, as it creates a firmer platform to push against. In a short-distance running race, acceleration off the block is everything. Cheetahs, the champion of short-distance runners of the animal kingdom, have non-flexible claws that give a similar advantage.
It is possible—just—that the differences in physical structure are the result of long and rigorous training. But it is unlikely. Far more probable is that the old saying of coaches, that great short-distance runners are born not made, is true. Everyone else, games masters included, should just get used to the idea.
Which ofthe followings is NOT included in the latest evidence gathered by Dr. Lee and Dr. Piazza
A:The toes of their short-distance runners are longer than those of common people. B:Short-distance runners tend to have a higher proportion of fast-contracting muscle fibres in their legs. C:In short-distance runners, the length of the lever of bone that the Achilles tendon pulls on is considerably shorter. D:The average length of toes of the tested common people is 7.3cm.
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.
They looked at seven university sprinters who specialize in the 100-metre dash and five 200-metre specialists, and compared them with 12 non-athletic university students of the same height. In particular, they looked at the sizes of bones of the toes and heel. They also used ultrasonic scanning to measure the sliding motion of the Achilles tendons of their volunteers as their feet moved up and down. This allowed them to study the length of the lever created by the tendon as it pulls on the back of the heel to make the foot flex and push off the ground.
Dr. Lee and Dr. Piazza found that the toes of their short-distance runners averaged 8.2cm in length, while those of common people averaged 7.3cm. The length of the lever of bone that the Achilles tendon pulls on also differed, being a quarter shorter in short-distance runners.
These findings suggest short-distance runners get better contact with the ground by having longer toes. That makes sense, as it creates a firmer platform to push against. In a short-distance running race, acceleration off the block is everything. Cheetahs, the champion of short-distance runners of the animal kingdom, have non-flexible claws that give a similar advantage.
It is possible—just—that the differences in physical structure are the result of long and rigorous training. But it is unlikely. Far more probable is that the old saying of coaches, that great short-distance runners are born not made, is true. Everyone else, games masters included, should just get used to the idea.
A:The toes of their short-distance runners are longer than those of common people B:Short-distance runners tend to have a higher proportion of fast-contracting muscle fibres in their legs C:In short-distance runners, the length of the lever of bone that the Achilles tendon pulls on is considerably shorter D:The average length of toes of the tested common people is 7.3cm
A student is (allowed) to (enter into) this room (only if) a teacher (has given) permission.（ ）
A:allowed B:enter into C:only if D:has given
Passage 4
| Sporting activities are essentially
modified forms of hunting behavior. Viewed biologically, the modern footballer
is in reality a member of a hunting group. His killing weapon has turned into a
harmless football and his prey into a goalmouth. If his aim is accurate and he
scores a goal, he enjoys the hunter’s triumph of killing his prey. To understand how this transformation has taken place we must briefly look back at our forefathers. They spent over a million years evolving (进化) as cooperative hunters. Their very survival depended on success in the hunting field. Under this pressure their whole way of life, even their bodies, became greatly changed. They became chasers, runners, jumpers, aimers, throwers and prey killers. They cooperated as skillful male group attack. Then about ten thousand years ago, after this immensely long period of hunting the food, they became farmers. Their improved intelligence, so vital to their old hunting life, was put to a new use—that of controlling and domesticating (驯养) their prey. The hunt became suddenly out of date. The food was there on the farms, awaiting their needs. The risks and uncertainties of the hunt were no longer essential for survival. The skills and thirst for hunting remained, however, and demanded new outlets. Hunting for sport replaced hunting for necessity. This new activity involved all the original hunting sequences (后果), but the aim of the operation was no longer to avoid starvation. Instead the sportsmen set off to test their skill against prey that was no longer essential to their survival. To be sure, the kill may have been eaten, but there were other purposes, much simpler of obtaining a meaty meal. |
A:skillful sportsmen B:successful farmers C:runners and jumpers D:cooperating hunters
以下程序的运行结果为______。
char *c []= "ENTER", "NEW", "POINT", "FIRST" ;
char **cp []= c+3, c+2, c+1, c;
char ***cpp=cp;
main （ ）
printf ("%s/n",**++cpp);
A:ENTER B:NEW C:POINT D:FIRST
以下程序的运行结果为______。
char *c []= "ENTER", "NEW", "POINT", "FIRST" ;
char **cp []= c+3, c+2, c+1, c;
char ***cpp=cp;
main （ ）
printf ("%s/n",**++cpp);
A:ENTER B:NEW C:POINT D:FIRST
