马克。吐温所写的以十六世纪英国为背景的历史小说是（）A、《镀金时代》 B、《王子与贫

阅读下列材料,从A、B、C、D四个选项中选出最佳答案,并将其番号填入题前括号内. 

    My name is Chen Lan.My home is in Gulangyu.Do you know it?It is in Xiamen.It is near the sea(海).

Gulangyu is a small place,but it is very nice and clean.There are no cars,no buses.People only walk.So it

is very quiet.

    Our house is in the middle of Gulangyu.Behind our house there is a big old tree.My grandfather tells me

that the tree is very,very old.There are many birds in the tree.We call it a "bird tree".Our house is near the

sea.The sea is big and blue.There are a lot of fish in the sea.After school,I go there and catch(捉) fish with my friends.It is very interesting.I like fish and I like catching fish.

1. Chen Lan is from _______.

A.Jiangsu

B.Zhejiang

C.Hunan

D. Xiamen

2. What is not in this passage?

A.The cars and buses.

B.The fish.

C.Her parents.  

D.Her friends.

3. What is behind our house?

A. a river      

B. a sea        

C. an old tree    

D. fish

4. How is the sea?

A.small          

B. big          

C. blue      

D. B and C

5.Why do they call the tree a "bird tree"?

A. Because it is like a bird.    

B. Because it is very old.

C. Because there are many birds in it.  

D. Because they like it.

氯化亚铜(CuCl)是白色粉末，不溶于水、乙醇，熔点422 ℃，沸点1366 ℃，在空气中迅速被氧化成绿色，常用作有机合成工业中的催化剂。以粗盐水(含Ca^2＋、Mg^2＋、SO₄^2－等杂质)、Cu、稀硫酸、SO₂等为原料合成CuCl的工艺如下：

（1）在粗盐除杂的反应I中加Na₂CO₃溶液的作用是                                   ；

滤渣的主要成分：                                       。

（2）反应Ⅱ完成后溶液中主要溶质是                                     。

（3）反应IV和VI都是制备CuCl的化学过程：

①反应IV加入的Cu必须过量，其目的是                                      。

②写出反应VI的离子方程式                                                 。

（4）反应VI后，过滤得到CuCl沉淀，用无水乙醇洗涤沉淀，在真空干燥机内于70 ℃干燥2小时，冷却，密封包装即得产品。于70℃真空干燥的目的是                           。

技术相机在操作上比单反相机更具优势的是（）。

A、灵活性

B、轻便性

C、精确度高

D、精确自由的调节性

医院采购药品应本着下列哪种原则

A．价格第一
B．经济效益第一
C．质量第一
D．药效第一
E．其他

根据投射方向是否垂直于轴测投影面，轴测投影可分为正轴测投影和（）两类

A.正二测投影

B.正等测投影

C.斜二侧投影

D.斜轴测投影