问题 完形填空
完形填空。
     Hello! I'm Li Xiang. I want to introduce my school to 1 .   Our school is very 2 .   There are about 1,900 3 and 100
teachers. When you 4 the school gate (大门),   you can see a tall building 5 you. Our classrooms and the teachers'
6 are in the building. There is a 7 behind the building, 8 we can borrow (借) books from it. Next to 9 , there is a gym.
We can 10 basketball, football and tennis. Is there a dining hall in our school? I will tell you next time. Bye!
( )1. A. me        
( )2. A. big      
( )3. A. teachers  
( )4. A. stand up    
( )5. A. next       
( )6. A. universities
( )7. A. library  
( )8. A. but          
( )9. A. there      
( )10.A. play        
B. them   
B. long      
B. offices  
B. come into
B. behind    
B. hotels    
B. gym      
B. too        
B. here      
B. meet     
C. you          
C. happy        
C. classrooms  
C. sit down    
C. in front of  
C. homes        
C. lab          
C. and          
C. one          
C. match        
D. us                
D. tall              
D. students          
D. open              
D. in the front of    
D. offices            
D. dining hall        
D. or                
D. it                
D. playing            
答案

1-5 CADBC  6-10 DACDA

单项选择题
填空题

某研究性学习小组将一定浓度Na2CO3溶液滴入CuSO4溶液中得到蓝色沉淀。

甲同学认为两者反应生成只有CuCO3一种沉淀;

乙同学认为这两者相互促进水解反应,生成Cu(OH)2一种沉淀;

丙同学认为生成CuCO3和Cu(OH)2两种沉淀。

(查阅资料知:CuCO3和Cu(OH)2均不带结晶水)

Ⅰ.按照乙同学得理解Na2CO3溶液和CuSO4溶液反应的化学反应方程式为

                                                                 

在探究沉淀物成分前,须将沉淀从溶液中分离并净化。具体操作为①过滤②洗涤③干燥。

Ⅱ.请用下图所示装置,选择必要的试剂,定性探究生成物的成分。

(1)各装置连接顺序为                                  

(2)装置C中装有试剂的名称是                            

(3)能证明生成物中有CuCO3的实验现象是                  

Ⅲ.若CuCO3和Cu(OH)2两者都有,可通过下列所示装置进行定量分析来测定其组成。

(1)装置C中碱石灰的作用是                         ,实验开始时和实验结束时都要通入过量的空气其作用分别是                                            

                                                                          

(2)若沉淀样品的质量为m克,装置B质量增加了n克,则沉淀中CuCO3的质量分数为