16岁，女，腹部胀大1个月，肛诊：左附件区触及新生儿头大实质肿瘤，血清甲胎蛋白值6.

骄傲的蜗牛

       很久以前，蜗牛长着一对翅膀，四只脚，一对触(chù)角，在空中自由  地飞舞着。   

       在一次重大的飞行比赛中，蜗牛遥遥领先，  （用，甩）下了所有的对手，夺得了冠军。于是，奖杯便授给了蜗牛。∥    

       蜗牛得了奖杯，得意洋洋地飞舞着，叫喊着，这以后，它把奖杯时刻带在身边，生怕别人不知道它是飞行冠军。可是，这奖杯很大很重，蜗牛背上它，就只能在地上爬行了。晚上，蜗牛怕别人偷去奖杯，它就睡在奖杯里。 好心的朋友见蜗牛背着沉重的奖杯，（艰 坚）难地爬行着，便劝它把奖杯放下来。蜗牛却把别人的好心当成了恶意。从此以后，再也没有人劝它了。∥   

       天长日久，蜗牛和奖杯连在一起了。它再也不能飞行了，只能背着沉重的  奖杯，在地上慢慢地爬行。由于它睡觉时头缩在奖杯里，现在只能勉强地从奖  杯里（伸  申）出长着一对触角的头。    

       看，荣誉（竞  竞）成了蜗牛的负担。∥  

1．这则故事属于(    )故事。我还知道这样的故事有_______、_______、________。

2．画去括号里不正确的字词。

3．文中已用“∥”分段，写出第二段主要说了什么。

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 4．这则故事告诉我们一个什么道理？

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什么是波分复用器的插入损耗？

当活塞运动装置对中不良导致拉缸时，可从（）与（）配合间隙进行分析判断。

A．气缸／活塞

B．气缸／活塞环

C．滑块／导板

D．活塞／活塞环

足球运动是目前全球体育界最具影响力的项目之一，深受青少年喜爱。如图所示为四种与足球有关的情景。下列说法正确的是（）

A.甲图中，静止在草地上的足球受到的弹力就是它的重力

B.乙图中，静止在光滑水平地面上的两个足球由于接触而受到相互作用的弹力

C.丙图中，踩在脚下且静止在水平草地上的足球可能受到3个力的作用

D.丁图中，落在球网中的足球受到弹力是由于球网发生了形变

The human Y chromosome—the DNA chunk that makes a man a man—has lost so many genes over evolutionary time that some scientists have suspected it might disappear in 10 million years. But a new study says it’ll stick around.
Researchers found no sign of gene loss over the past 6 million years, suggesting the chromosome is "doing a pretty good job of maintaining itself," said researcher David Page of the Whitehead Institute for Biomedical Research in Cambridge, Mass.
That agrees with prior mathematical calculations that suggested the rate of gene loss would slow as the chromosome evolved, Page and study co-authors note in Thursday’s issue of the journal Nature. And, they say, it clashes with what Page called the "imminent demise" idea that says the Y chromosome is doomed to extinction.
The Y appeared 300 million years ago and has since eroded into a dinky chromosome, because it lacks the mechanism other chromosomes have to get rid of damaged DNA. So mutations have disabled hundreds of its original genes, causing them to be shed as useless. The Y now contains only 27 genes or families of virtually identical genes.
In 2003, Page reported that the modern-day Y has an unusual mechanism to fix about half of its genes and protect them from disappearing. But he said some scientists disagreed with his conclusion. The new paper focuses on a region of the Y chromosome where genes can’t be fixed that way.
Researchers compared the human and chimpanzee versions of this region. Humans and chimps have been evolving separately for about 6 million years, so scientists reasoned that the comparisons would reveal genes that have become disabled in one species or the other during that time.
They found five such genes on the chimp chromosome, but none on the human chromosome, an imbalance Page called surprising. "It looks like there has been little if any gene loss in our own species lineage in the last 6 million years," Page said. That contradicts the idea that the human Y chromosome has continued to lose genes so fast it’ll disappear in 10 million years, he said. "I think we can with confidence dismiss … the ’imminent demise’ theory," Page said.
Jennifer A. Marshall Graves of the Australian National University in Canberra, a gene researcher who argues for eventual extinction of the Y chromosome, called Page’s work "beautiful" but said it didn’t shake her conviction that the Y is doomed.
The only real question is when, not if, the Y chromosome disappears, she said. "It could be a lot shorter than 10 million years, but it could be a lot longer," she said.
The Y chromosome has already disappeared in some other animals, and "there’s no reason to expect it can’t happen to humans," she said. If it happened in people, some other chromosome would probably take over the sex-determining role of the Y, she said.

Page seems to believe that
[A] the gene loss of Y chromosome is sure and fast.
[B] the gene loss of Y chromosome is quite slow.
[C] the Y chromosome is facing "imminent demise".
[D] the Y chromosome will be replaced by a new one.