Choose the best answer for the following sentence:
Sometimes it is ____________ to find suitable books for our children. 
A. difficult
B. difficulty                     
C. difficultly                   
D. difficulties

Choose the best answer for the following sentence:
It’s time we concentrated on our _____________ business.
A. core                
B. heart           
C. center                
D. essence

Choose the best answer for the following sentence:
My girlfriend arrived after I ________________ for her about half an hour. 
A. was waiting           
B. had been waiting 
C. have been waiting                 
D. have waited

Choose the best answer for the following sentence:
We are in an unbalanced situation when women ______________ over 75% of our staff.
A. contract                
B. cover                        
C. consist                    
D. comprise

Choose the best answer for the following sentence:
___________, you’d know what we're talking about now.
A.  If you aren’t late
B. If you weren’t late
C. If you wouldn't be late
D. If you hadn't been late

Choose the best answer for the following sentence:
The number of the world’s elephants is restricted ____________ some certain countries. 
A. at                  
B. into                    
C. to                 
D. upon

Choose the best answer for the following sentence:
Students _____________ the soccer team are asked to attend this afternoon at five.
A. interesting to join - tryouts              
B. interested to join - the tryouts
C. interested in joining - tryouts
D. to be interested joining - a try-out

Choose the best answer for the following sentence:
Last night they gave every __________ of enjoying themselves at the party. 
A. appearance                        
B. intention                     
C. attempt                    
D. trial

Choose the best answer for the following sentence:
He fell down when he ________________ towards the church. 
A. run                
B. runs            
C. was running                
D. had run

Choose the best answer for the following sentence:
I ____________________ them since we met at Ann's birthday party.
A.  have been knowing                
B. knew 
C. have known               
D. know