与二进制小数0.1等值的十六进制小数为( )。A．0.1 B．0.2 C．0.4

阅读下面的文字，完成下面的题。

　　①是不是岁月如此的沉重，注定我要成为一个步履维艰的浪者，是不是生命有着无法承受的厚重，才要远离熟悉的家门。

　　②总想起离别好久的家门，总叫人黯然神伤。在这个身在异乡为异人的他乡，怎叫人不想起遥远的门呢？

　　③也许思念太长了，街道太长了，夜也太长了，如千年的月光散了一地长，长长地撒在城市的每个角落，梦醒间，还以为是故乡门前窗台的霜。

　　④月色下有一落叶飘舞，从树枝上飘落下来，这瞬间的漂泊落地，又随风而起，何时风尘落定才有你的安身之处呢？

　　⑤记忆中的门是那木质混厚斑驳中透着红漆的那扇。冬日的阳光撒了一地，在“吱呀”的一声中迎来满屋的光芒，那种阳光很舒服，暖洋洋的，伸一个懒腰最是惬意，“呵”一口热气，可以看到它在空气中散去，那感觉很好。

　　⑥黄昏的时候一定要找到回家的门，不然奶奶会不厌其烦地在田间地头村里巷尾喊着乳名，那儿时的愉悦和恐慌总在那“哐”的一声关门中温暖着整个细胞。走进梦里还有小狗卧守在门边给人一份安然。

　　⑦年龄渐长，岁月依然保留着门的那份平和，看不出游逝的时光改变了它什么，依旧是那扇木质斑驳的门，还有门前那棵枣树，以及枣树旁边固执地成长为强者的梧桐，我曾亲手赐予它们生命，我好像预言了多年以后那份背道而驰的诀别，在很远的地方，我只想看到参天的树木耸立门前，看到树的叶缘叶黄，可以知道四季的变更。那门前的老人，她年如一日地远眺着，虽然她看不清很远的来路，但她知道固守能给她带来喜悦，在某个细雨飘洒的日子，会有流浪的人，溅了一身的泥水归来。

　　⑧漂泊在门的远方，门离我遥遥几千里。本不愿漂泊，因为离不开那扇木质斑驳的门，当我看到门前的梧桐以一种强者的躯干俯瞰着下面时，它已不再是一棵树了，仿佛成了一个守护者。思索千遍，选择了千遍，煎熬了很久，在成长中学会了放弃，在放弃中学会了选择，在选择中又学会了坚强。

　　⑨起程时故作沉着，把感性的泪化作坚强的背影留给日夜思念的人。早已看不见那扇门了，我才依恋地频频回首。好一扇门啊，如此走了很远，才让人想起门就是通往温暖的家的那个进出了无数次却不曾留意的“坎”。后来明白，门还是一个难进难出的情结。

　　⑩房子换了坚固点的，门也换了铁制的。但记忆中总是那扇斑驳点点的木门，它一直存在着，每次回乡下，远远地看见那门，还有门前的树，以及树下的老人。原来走得再远也不过是在门前晃了一眼，离不开的还是那门。

　　从未嫌弃那红漆斑驳的木门，虽它没有铁制的门坚硬无比，但它那朴实的外表总给人一种安全和信任。出了门，说是远门，我敲开了更多的门。繁华的远方没有那扇木质的门，开门之后，听不到“吱呀”的声音——那如此纯粹如此让人沉醉如此让人温暖的声音。没有“吱呀”的声响，肯定也没有厚道的乡情和憨实的微笑了。

　　在异地有了一扇临时的门，那铁制的门很厚实坚硬，我很少带钥匙，可我不知道那门是要用钥匙才能为我开启的，总以为门会听到我的脚步声会自动地打开，或轻掩着，等我轻轻一推就能开了。可很多次，我被门——准确地说是那临时的门——拒之门外，叫我好一番落寂和无助。门开着是一种期待，在家里门总是开着，那门只能从屋子里才能闩上的，微弱的灯光下，总有人为你守着门后的那份疲倦，有了熟悉的脚步声，那门自然就开了，还有那小狗总在脚跟尾随好久才肯离去。

　　这双纳底的布鞋，走了好远的路，磨不破的是长长的思念，思念之中有了一种坚强的斗志。门前期盼的一双双眼睛，望穿了步履维艰的归期，望成了愁，两处的愁。

　　学着小孩掰起手指数起数来，数到小指，再数大拇指，归期竟还有如此之遥远。于是只能在梦里念起远处的门来，才又明白，那扇门是家，进了家必要开那扇门，门也就成了一个起点，最终还是终点。怎么不如此思念呢？哪怕你再坚强，错把泪水当汗水。

　　不能不思念啊，我虽把相思之情隐藏着很深，可我不小心一笑间竟把思念打湿，让这凌空的翅膀动弹不得。还是思念那扇门。

　　我知道门有多种，门有千万扇，我寻求好久，走了好远，可终究是离不开那扇门，那扇听到我脚步声便自然开启的门，我要的也就是那扇只为我打开和等待的门。

1．第④段中写“落叶飘舞”在表情达意上起了什么作用？

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2．根据文中内容完成问题。

（1）文中有一个贯穿全文的细节起了很好的作用，请你指出这个细节并简析其好处。

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（2）作者为什么说自己现在城市的家的家门是“临时的门”？

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3．作者所怀念的“门”有哪些特点使作者不能忘怀？（答出两点即可。）

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械振动按产生原因可分（）、（）、。

函数y=-（x+5）²+7的对称轴是______，顶点坐标是______，图象开口向______，当x______时，y随x 的增大而减小，当______时，函数y有最______值，是______．

C

A scientist working at her lab bench and a six-old baby playing with his food might seem to have little in common.After all,the scientist is engaged in serious research to uncover the very nature of the physical world,and the baby is,well, just playing…right?Perhaps,but some developmental psychologists()have argued that this“play”is  more like a scientific investigation than one might think.

Take a closer look at the baby playing at the table.Each time the bowl of rice is pushed over the table edge,it

falls in the ground---and, in the process, it belongs out important evidence about how physical objects interact ; bowls of rice do not flood in mid-sit, but require support to remain stable. It is likely that babies are not born knowing the basic fact of the universe; nor are they ever clearly taught it. Instead, babies may form an understanding of object support through repeated experiments and then build on this knowledge to learn even more about how objects interact. Though their ranges and tools differ, the baby’s investigation and the scientist’s experiment appear to share the same aim(to learn about the natural world ), overall approach (gathering direct evidence from the world), and logic (are my observations what I expected?).

Some psychologists suggest that young children learn about more than just the physical world in this way---that they investigate human psychology and the rules of language  using similar means. For example, it may only be through repeated experiments, evidence gathering, and finally overturning a theory, that a baby will come to accept the idea that other people can have different views and desires from what he or she has, for example, unlike the child , Mommy actually doesn’t like Dove chocolate.

Viewing childhood development as a scientific investigation throws on how children learn ,but it also offers an inspiring look at science and scientists. Why do young children and scientists seem to be so much alike? Psychologists have suggested that science as an effort ---the desire to explore, explain, and understand our world---is simply something that comes from our babyhood. Perhaps evolution provided human babies with curiosity and a natural drive to explain their worlds, and adult scientists simply make use of the same drive that served them as children. The same cognitive systems that make young children feel good about feel good about figuring something out may have been adopted by adult scientists. As some psychologists put it, ”It is not that children are little scientists but that scientists are big children.”

According to some developmental psychologists,（）

A. a baby’s play is nothing more than a game.

B. scientific research into babies; games is possible

C. the nature of babies’ play has been thoroughly investigated

D. a baby’s play is somehow similar to a scientist’s experiment

在物流系统本量利分析中，（）是一个十分重要的概念。

A．边际成本

B．边际税率

C．边际贡献

D．边际资本