Choose the best answer for the following sentence:
I couldn’t cut the grass because the lawn mower ____________ a few dayspreviously.
A. broke down               
B. has been broken 
C. had broken down              
D. breaks down

Choose the best answer for the following sentence:
Since 1980, scientists all over the world ________________ a lot of things to fight against AIDS.
  
A. have done          
B. are doing             
C. did             
D. had done

Choose the best answer for the following sentence:
Learning the ___________ skills and techniques may not be as fun and engaging for the players. 
A. defensible                  
B. defender                  
C. defendant                 
D. defensive

Choose the best answer for the following sentence:
The young athlete was prevented from the match as the police found a ______________ of drugs hidden in his bags before the match began. 
A. quantity                    
B. quality                      
C. piece                 
D. thread

Choose the best answer for the following sentence:
I didn’t have much time, but I __________ visit a lot of places of interest in London.
A. can  
B. must
C. was able to
D. had to

Choose the best answer for the following sentence:
When they returned, my uncle _______________ by the news that the little old lady had made an appearance.
A. overwhelmed expectedly
B. expectedly was overwhelmed
C. was expectedly overwhelmed
D. expectedly overwhelmed

Choose the best answer for the following sentence:
Liz moved _____________ .
A. grace 
B. graceful 
C. gracefully 
D. on grace

Choose the best answer for the following sentence:
 _______________ is a game played in a swimming pool in which two teams of swimmers
try to score goals with a ball. 
A. Water polo                       
B. Rowing                      
C. Swimming                     
D. Water skiing

Choose the best answer for the following sentence:
If you __________ a choice, which country would you visit? 
A. have         
B. had            
C. have had          
D. will have

Kết quả đúng trong các kết quả sau: lim-3x2+2x-52x2-7 bằng
A. 32.
B. 23.
C. -23.
D. -32.