“5·7”空难发生后,搜救人员运用声呐设备探测坠入大海中的飞机残骸,实际上这是利

题型:填空题

问题:

“5·7”空难发生后,搜救人员运用声呐设备探测坠入大海中的飞机残骸,实际上这是利用_____,同时也说明_____可以传声 .

考点:回声及回声测距离的应用声音的传播
题型:填空题

加重症支气管哮喘的治疗中禁用的药物是()

A.肾上腺皮质激素

B.吗啡

C.抗生素

D.氨茶碱

E.碳酸氢钠

题型:填空题

将胚的各部分结构和将来的发育情况用线连起来。

a.胚根A.发育成茎和叶
b.子叶B.发育成连接根与茎的部分
c.胚芽 C.发育成根
d.胚轴 D.为种子萌发提供营养物质
题型:填空题

短文改错。

     文中共有10处语言错误,每句中最多两处。错误涉及一个单词的增加、删除或修改。

     增加:在此处加一个漏词符号(∧),并在其下面写出该加的词。

     删除:把多余的词用斜线(\)划掉。

     修改:在错的词下划一横线,并在该词下面写出修改后的词。

     注意:

     1、每处错误及修改均仅限一词;

     2、只允许修改10处,多者(从11处起)不计分。

Dear Wei Fang,

     It's a long time since I heard from you in last time. Now I'd like to tell you a impressive story that

happened on the first day of my teaching career.

    A boy, Li Ming, whom father died a year ago, was late for school. He stood outside the classroom

quiet. I smiled at him and let him come. After a while, he began to cry. Seeing this, I walked to him and

asked what has happened. He told me his mother was ill but he had to get some medicine for her. At the

same time he apologized to me for his lateness. Moved by his word, I praised him for his deeds and

decided to sing a song was named "Mother" for the students. From then on I began to realize we should

respect our parents and did our best to help them. Do you think so? I'm looking forward to your early

reply.

_____________________________________________________________________________

题型:填空题

(共8分)(1)在盛有鸡蛋白溶液的试管中,加入(NH4)2SO4浓溶液,可使蛋白质的溶解度降低而从溶液中析出,这种作用叫做_____  ___。继续加水时,沉淀会_____  ___,并不影响原来蛋白质的性质。

(2)在盛有鸡蛋白的溶液的试管中,加入CuSO4溶液,蛋白质会发生性质的改变而凝结起来,这种作用叫做_______  _,此过程         (填“可逆”“不可逆”)。

题型:填空题

数据库、数据库系统、数据库管理系统三者之间的关系是______。

A.数据库包含数据库系统和数据库管理系统

B.数据库系统包含数据库和数据库管理系统

C.数据库管理系统包含数据库和数据库系统

D.以上都不正确

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