The passage mainly discusses ______.  
A.an experiment done by Dr. Wilder Penfield    
B. human memory 
C.chemical reactions in the brain  
D.a computer’s memory compared with human’s

The word bonds in paragraph 2 is closest in meaning to ______.
A.agreements         
B.connections         
C.agencies  
D.effects

According to most theories, which of the following is NOT affected by memory trace?
A.Learning           
B.Memory loss     
C.Retention
D. Retrieval possible for a memory

According to the passage, memory trace ______.
A.presents information at a particular time
B. is possibly made by structural changes in the brain
C.has a huge capacity for information storage  
D. is the connection between brain cells

It can be inferred from the first paragraph that ______.
A.before studies were carried out, people had had false assumptions about human memory
B.Dr. Wilder Penfield disagreed with other researchers’ conclusions
C. the Canadian scientist tried to prove that other researchers had been wrong
D.it is easy for people to recall events that they have suddenly forgot

The word emerged  in paragraph 1 mostly means ______.
A.appeared               
B.integrated         
C.originated  
D.vanished

The word their in paragraph 1 refers to ______.
A.brains           
B.subjects    
C.events
D. dreams

According to the passage, Dr. Wilder Penfield proved that with electric stimulation, people can ______.
A.remember all the incidents in their live
B.elicit some special events from the past
C.recollect particular experiences from the past      
D. suddenly recall their dreams in detail

____with the size of the whole earth, the highest mountains do not seem high at all.
A.If you compare     
B. Compare them          
C.When compared
D. A comparison

The leaves of the white mulberry provide food for silkworms, ______ silk fabrics are woven.
A.from whose cocoons 
B.from cocoons   
C.whose cocoons are from
D.whose cocoons