题目内容
Why don’t birds get lost on their long flights from one place to another Scientists have puzzled over this question for many years. Now they’re beginning to fill in the blanks.Not long ago, experiments showed that birds rely on the sun to guide them during daylight hours. But what about birds that fly by night Tests with artificial stars have proved that certain night - flying birds are able to follow the stars in their long- distance flights.A dove (鸽子)had spent its lifetime in a cage and had never flown under a natural sky. Yet it showed an inborn ability to use the stars for guidance. The bird’s cage was placed under an artificial star-filled sky. The bird tried to fly in the same direction as that taken by his outdoor cousins. Any change in the position of the artificial stars caused a change in the direction of his flight.But the stars are apparently their principal means of navigation(航行)only. When the stars are hidden by clouds, they seemingly find their way by such landmarks as mountain ranges, coast lines, and river courses. But when it’s too dark to see these, the doves circle helplessly, unable to find their way. In total darkness, doves().
查看答案
搜索结果不匹配？点我反馈
更多问题
阅读下面短文，回答下面问题。 父亲喜欢兰草，过些日子，就要到深山中一趟，带回些野兰来培栽。几年问，家里庭院就有了百十余品种，像要做一个兰草园圃似的。方圆十几里的人就都跑来观赏，父亲并不因此而得意，反而有几分愠怒。以后又进山去、可不再带回那些野生野长的兰草了。这事使我很奇怪，问他，又不肯说，只是有一次再进山的时候，要我和他一块去访兰。 我们走了半天，一直到了山的深处。那里有一道瀑布，从几十丈高的山崖直直垂下，老远就听到了轰轰隆隆的响声，水沫扬起来，弥漫了半个天空，日光在上面浮着，晕出七彩迷丽的虚幻。我们沿谷底走，便看见有很多野兰草，盈尺高的，都开了淡淡的兰花，像就地铺着一层寒烟；香气浓烈极了，气浪一冲，站在峡谷的任何地方都闻到了。 我从未见过这么清妙的兰草，连声叫好，要动手挖。父亲却把我制止了，问道：“你觉得这里的兰草好呢，还是家里的那些好呢” 我说：“这里的好!” “怎么好呢” 我却说不出来。“好像是味儿不同吗” “是的。” “这是为什么一样的兰草，长在两个地方就有两个味儿” 父亲说：“兰草是空谷的幽物，得的是天地自然的原气。长的是山野水畔的趣姿；一经培栽，便成了玩赏的盆景。” “但它确实叶更嫩、花更繁更大了呢!” “样子似乎是美了，但美得太甜、大媚，格调也就俗了。” 父亲的话是对的，但我不禁惋惜：这么精神的野兰在这么个空谷僻野，叶是为谁长的，花是为谁开的，会有几个人欣赏它呢 “这正是它的不俗处。它不为被人欣赏而生长，却为着自己的特色而存在着，所以它才长得叶纯，开得花纯，楚楚的有着它的灵性。” 父亲拉我坐在潭边。他看着兰，也在看着我，说；“做人也是这样啊，孩子!人活在世上，不能失了自己的真性，献媚处事，就像盆景中的兰草一样降了品格；低俗的人不会对社会有贡献的。” 我深深地记着父亲的话。从那以后，已经是15年过去了，我一直未敢忘却过。 (贾平凹《访兰》) 不属于野兰不俗之处的一项是：
设在工程文件中有一个标准模块，其中定义了下列记录类型： Type Books Name As String*10 TelNum As String*20 End，Type 在窗体上画一个名为Command1的命令按钮，要求当执行事件过程Command1 Click 时，在顺序文件Person．txt中写入一条Books类型的记录。下列能够完成该操作的事件过程是 ( )。
One day I was having a hearty lunch at a fast-food restaurant when an old couple entered slowly. They (36) a meal at the counter. And then they took a seat and began to (37) food out of the dish. On the table there was one small hamburger, one pair of chicken wings and one orange juice. The elderly man (38) what they had into two halves and put (39) in front of his wife with great care.He tasted the juice. His wife tasted one as well and set the paper cup (40) them. "What a(n) (41) couple! What they can (42) is just one meal for both of them," thought I. (43) the man started eating his chicken wings, I (44) to my feet, went towards them and told them that I was (45) to buy another meal for them. To my surprise, he (46) refused me and said that they considered it a good (47) to share everything they had. (48) . the woman stopped eating. Instead she just sat there and (49) him eat, and taking turns to drink the juice. Once again I (50) to buy them something to eat but they said "No". After a moment, when he was (51) his mouth with a napkin, I (52) not bear it any longer. Therefore, I made an offer a third time.(53) being refused again, I asked the old lady (54) , "Could you tell me why you aren’t eating You said that you both shared everything. (55) are you waiting for on earth" "The teeth," she answered. 43().
在窗体上画一个命令按钮，名称为Command1，然后编写下列代码： Option Base 0 Private Sub Command1 Click() Dim A1(4)As Integer，A2(4)As Integer For k=0 To 2 A1(k+1)=InputBox(”请输入一个整数”) A2(3-k)=A1(k+1) Next k Print A2(k) End Sub 程序运行后，单击命令按钮，在输入对话框中依次输入2、4、6，则输出结果为( )。
微信支付 
支付宝支付