国家图书馆的主要职能有哪些？

病历摘要：患者男性，55岁，有20年吸烟史，每天10支。持续性进行性声嘶1月，伴咳嗽、咽异物感，间接喉镜检查会厌大，遮盖声门

纤维喉镜下检查：左侧声带、前联合菜花状肿物，左侧声带活动受限，右侧声带正常，双侧环勺关节正常。颈部未及淋巴结，肿物做了活检，报告未出，请问需鉴别的疾病有：（）

A.喉结核

B.慢性单纯性喉炎

C.广东瘤

D.声带息肉

E.喉 * * 状瘤

F.喉蹼

G.喉淀粉样瘤

小莉和小颖是两个很要好的朋友，生活中互相帮助，学习上你追我赶．在一天体育大课间活动中，她们比赛“一分钟跳绳”，共比赛了五次，成绩分别如下：

小莉：89，67，89，92，96小颖：86，62，89，92，92

她们各自利用所学习的数学知识进行了一番分析思考．小莉说：你的成绩比我好；小颖说：我们的成绩一样．

（1）请你分析她们各自的理由；

（2）你认为还可以从哪个方面来评价谁的成绩更好些？说一说你的理由．

How I Turned to Be Optimistic

I began to grow up that winter night when my parents and I were returning from my aunt＇s house, and my mother said that we might soon be leaving for America. We were on the bus then. I was crying, and some people on the bus were turning around to look at me. I remember that I could not bear the thought of never hearing again the radio program for school children to which I listened every morning.

I do not remember myself crying for this reason again. In fact, I think I cried very little when I was saying goodbye to my friends and relatives. When we were leaving I thought about all the places I was going to see—the strange and magical places I had known only from books and pictures. The country I was leaving never to come back was hardly in my head then.

The four years that followed taught me the importance of optimism, but the idea did not come to me at once. For the first two years in New York I was really lost—having to study in three schools as a result of family moves. I did not quite know what I was or what I should be. Mother remarried, and things became even more complex for me. Some time passed before my stepfather and I got used to each other. I was often sad, and saw no end to “the hard times. ”

My responsibilities in the family increased a lot since I knew English better than everyone else at home. I wrote letters, filled out forms, translated at interviews with Immigration officers, took my grandparents to the doctor and translated there, and even discussed telephone bills with company representatives.

From my experiences I have learned one important rule: Almost all common troubles eventually go away! Something good is certain to happen in the end when you do not give up, and just wait a little! I believe that my life will turn out all right, even though it will not be that easy.

小题1:How did the author get to know America?

A．From her relatives

B．From her mother

C．From Books and pictures

D．From radio programs小题2:Upon leaving for America the author felt       .

A．confused

B．excited

C．worried

D．amazed小题3:What can we learn about the author from Paragraph 4?

A．She worked as a translator

B．She attended a lot of job interviews

C．She paid telephone bills for her family

D．She helped her family with her English小题4:The author believes that      .

A．her future will be free from troubles

B．it is difficult to learn to become patient

C．there are more good things than bad things

D．good things will happen if one keeps trying

一种2n=20的植株与一种亲缘关系的2n=22的植株杂交产生了一个双2倍体，这个双二倍体的减数分裂产生的二价体个数（）。

A.21

B.42

C.84

D.168

管路效率大致与管道直径的（）次方成正比。

A、2

B、3

C、4

D、5