__________(53)
A.interview           
B.story        
C.time         
D.thing

__________(52)
A.generally    
B.mainly    
C.fully                
D. quickly

__________(51)
A.absence    
B.period      
C.difference           
D.conversation

__________(50)
A.conversation   
B.subject        
C.research 
D.topic

__________(49)
A.present     
B. absent   
C.concentrated    
D.mentioned

__________(48)
A.run  
B.reach       
C.range          
D.random

__________(47)
A.stories 
B.topics    
C.gossips   
D.conversations

__________(46)
A.researches 
B.things   
C.conversations    
D.gossiping

What does the passage mainly discuss?
A.Why some species of birds nest together         
B.How birds maintain body heat in the winter
C.Why birds need to establish territory    
D.How birds find and store food

The word “conserve ”in line 3 is closest in meaning to
A. watch 
B.retain   
C.share
D.locate