适量的维生素C对人体营养作用非常重要,可以提高免疫力,防治多种疾病。人体中维生素C的

题型:单项选择题

问题:

适量的维生素C对人体营养作用非常重要,可以提高免疫力,防治多种疾病。人体中维生素C的来源最好的途径是()。

A、多吃蔬菜和水果;

B、多服用维生素C片剂;

C、靠人体内自行合成

考点:陕西知识竞赛陕西科普知识竞赛(中学组)陕西科普知识竞赛(中学组)题库
题型:单项选择题

短文填空。

     Zhang Qin is a nineteen-year-old young man. Two years ago, when he 1______ middle school, he found

work in a shop. Usually he worked 2______ nine o'clock in the evening. When he got home, he always felt very

tired. After a quick supper he went to bed and fell 3______. So he never made any noise and his grandfather

was very pleased with him.

     One day he went back from work a little 4______. On his way home he met Li Jun, one of his 5______.

They were both very happy. Zhang Qin asked Li Jun to his house, and Li Jun agreed. Li Jun 6______ some fruit

and drink. They talked about their school, their teachers, their classmates and their 7______. They talked for a

long time. 

     "Have a look at your watch, please." Said Li Jun," What's the time now?"

     "Sorry, there is something wrong with my watch." Said Zhang Qin." Where is 8______?"

     "I 9______ it at home."

     Zhang Qin thought for a moment and found a way. He began to jump on the floor.

     The sound woke his grandfather up. The old man shouted 10______." It's twelve o'clock, Zhang Qin. Why

are you still jumping upstairs?"

      ( A. asleep B. future(s) C. downstairs D. finished E. until F. classmates G. left H. earlier I. brought J. yours )

题型:单项选择题

补充条件再解答。

1.车上原有68人,到站后下车了20人,__________,车上现在有多少人?

2.买每瓶2元的牛奶3瓶,____________,牛奶和饼干一共花了多少钱?

3.一支竹竿插入水里的部分有13米,___________,这支竹竿长多少米?

4.王小丽买了4个笔记本后,还剩12元,___________,她原来有多少元?

5.一个三角形三条边都一样长,___________,三角形三条边一共长多少米?

6.一座楼房,__________,这座楼房从一楼到四楼顶高多少米?

题型:单项选择题

在局麻药中加入肾上腺素的常用浓度是

A.1:1000~3000

B.1:5000

C.1:10000~30000

D.1:200000~500000

E.1:1000000

题型:单项选择题

目前一般认为扩张动脉段内径要大于或等于近端或远端动脉内径多少倍,才能诊断为动脉瘤

A.1.5倍

B.2倍

C.2.5倍

D.3倍

E.3.5倍

题型:单项选择题

下图表示葡萄糖跨膜运输的过程,据图分析正确的是()

A.该膜中的载体也能运输氨基酸

B.该膜可能是红细胞膜

C.该方式发生在被转运物质从低浓度到高浓度时

D.与该过程有关的细胞器是线粒体和核糖体

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