问题 选择题

如图中曲线①和②可以表示的是(  )

A.流经小肠的血液中,①表示氧气;②表示营养物质

B.人体注射乙脑疫苗后,①表示抗原;②表示相应抗体

C.在密封的酒窖内酿酒时,①表示二氧化碳;②表示酒精

D.进入冬季后,①表示青蛙的耗氧量;②表示鸟类的耗氧量

答案

A、小肠是吸收营养物质的主要场所,血液流经小肠后,营养物质会显著增多;流经小肠的血液循环部分是体循环的一部分,因此,血液流经小肠后,氧气会减少,二氧化碳会增多,但氧气不会减少到零.故说法错误.

B、从抗原、抗体相互作用的免疫机理分析,麻疹疫苗相当于抗原,接种到人体后,会刺激人体内的淋巴细胞产生抗体,从而对麻疹病毒起到免疫作用.抗体消灭抗原后,抗体仍然存留,因此抗原是含量变化是由多变少;抗体的含量变化是由少变多.故说法正确.

C、酵母菌发酵酿酒需要无氧的环境,容器密封,由于酵母菌的生殖繁殖,很快就会密封的容器中有限的氧气消耗完,因此急剧减少的物质1是氧气;在开始的生长繁殖过程中就会有二氧化碳产生,繁殖到足够数量之后,再发酵产生2酒精和二氧化碳,因此图象中在开始氧气的含量远高于2酒精的含量是错误的.故说法错误.

D、青蛙属于变温动物,体温随着环境的变化而变化,因此当进入冬季时,青蛙进入冬眠,新陈代谢非常缓慢,因此耗氧量很低,但也不至于为零.故说法错误.

故选:B

单项选择题

阅读下面短文,掌握其大意,然后从16-35各题所给的A、B、C、D四个选项中,选春最佳选项。

The journey my daughter Cathy has had with her swimming is as long as it is beautiful.

Cathy suffered some terrible 16  in her early childhood. After years of regular treatment, she  17  became healthy.

Two years ago, while Cathy was watching the Olympics, a dream came into her sweet little head—to be a swimmer. Last summer, she wanted to  18  out local swim team. She practiced hard and finally  19  it. The team practice,  20  was a rough start. She coughed and choked and could hardly  21  her first few weeks. Hearing her coughing bitterly one night, I decided to  22  her from it all. But Cathy woke me up early next morning, wearing her swimsuit  23  to go! I told her she shouldn’t swim after a whole night’s coughing, but she refused to  24  and insisted she go .

From that day on, Cathy kept swimming and didn’t  25  a single practice. She had a  26  intention within herself to be the best she could be. My ten—year—old was growing and changing right before my eyes, into this 27  human being with a passion and a mission. There were moments of  28  of course: often she would be the last swimmer in the race. It was difficult for Cathy to accept that she wasn’t a  29  ---ever. But that didn’t stop her from trying.

Then came the final awards ceremony at the end of the year. Cathy didn’t expect any award but was still there to  30  her friends and praise their accomplishments. As the ceremony was nearing the end, I suddenly heard the head coach  31  , “The highest honor goes to Cathy!” Looking around, he continued, “Cathy has inspired us with her  32  and enthusiasm.  33  skills and talents bring great success, the most valuable asset(财富)one can hold is the heart.”

It was the greatest  34  of my daughter’s life. With all she hade been  35  in her ten years, this was the hour of true triumph(成功).

16()

A.failure

B.pressure

C.loss

D.illness

选择题