票据上有伪造、变造的签章的，（）票据上其他真实签章的效力。 A.影响 B.不影响 C

WC5胶轮车无法起动的原因可能是（）。

A、气动系统气体压力偏低

B、起动马达已经损坏

C、阻风门没有打开

D、断油阀没有打开

如图所示，小车上的木块突然向左倾倒，发生这一现象的原因是（  ）

A．小车突然向左运动

B．小车突然向右运动

C．向右运动的小车突然停下

D．以上原因都有可能

为帮助人们设计健康的饮食方案。营养家将食物分为五类，并提倡合理膳食，下图是我国营养学家建议居民一日三餐对各类食物的摄取比例，请根据图回答问题。

 

（1）我们每天摄取的食物中，V 所占的比例最大，这是因为  　　   是人体最重要的供能物质。

（2）1913 年，俄罗斯“圣虎克号”的船员们在航行途中患了一种疾病，他们牙龈肿胀，容易出血。图中   　　   （填标号）类食物能防治这种病。

（3）处于生长发育时期的青少年应多吃一些含蛋白质、钙、磷和维生素丰富的食物，请你从图中选取合适的食物    　　　   ( 填标号) 。

RS、GPS和GIS被统称为3S技术，现已在地理学研究领域和国土整治中得到广泛运用。2010年5月1日，某校地学夏令营营员乘飞机前往我国某地进行考察。据此回答1~2题。

1、2010年5月1日，飞机前往目的地途中，每位营员都可随时查阅到自己的位置及飞临地区的人文、自然景观，采用的技术是[ ]

A、地理信息系统

B、遥感技术

C、遥感技术和全球定位系统

D、全球定位系统和地理信息系统

2、2010年5月3日，该地学夏令营的营员们在野外考察时，使用手持式全球定位系统信号接收机，屏幕上显示如下界面，据此判断营员们可能

A、在测量太行山山脉中某山峰的高度

B、在泰山采集岩石标本

C、在河西走廊调查荒漠化状况

D、在云贵高原调查植被破坏情况

Man first appeared on earth about 2 million years ago. Then he was little more than an animal; but early man had a big advantage over the animals. He had in his brain special groups of nerve cells, not present in animals, that enabled him to invent a language and use it to communicate with his fellow men. 46) This ability to speak was of great value because it allowed men to share ideas, and to plan together, so that tasks impossible for a single person could be successfully undertaken by intelligent team-work. Speech also enabled ideas to be passed on from generation to generation so that the stock of human knowledge slowly increased.
It was this special ability that put men far ahead of other living creatures in the struggle for existence. 47) He mastered darkness first with dim lights and later with brighter and brighter lamps, until he can now make for himself so dazzling a light with an arc lamp that, like the sun, it is too p for his naked eyes.
48) Man found that his own muscles were too weak for the work which he wanted to do; he explored many other forms of power until now he has his hands on the ultimate source of physical energy, the nuclear power. From man’s earliest days the flight of birds has raised his wonder and desire. Why should he not fly as they did Then he began to experiment. At last he learnt how to make the right machines to carry him through the air. Now he can fly faster than sound. Already he has plans for conquering space, and a series of experiments has been completed. 49) It will not be long now before man takes a giant step away from his planet and visits the moon, learning what it is like to have no weight to his body, no upward direction and no downward.
Man, always a wanderer, has to overcome the difficulty of adapting himself to different climates. 50) Fortunately, in spite of having no thick skin or warm fur to protect him, he is peculiarly p compared with other living creatures, most of whom are unable to live far outside the region that suits them best.