Giả sử khi thực hiện một phép chọn nào đó ta phải thực hiện theo phương án A hoặc phương án B. Thực hiện phương án A có m cách khác nhau và phương án B có n cách khác nhau. Khi đó phép chọn được thực hiện theo:
A. m.n cách khác nhau.
B. m + n cách khác nhau.
C. mn cách khác nhau.
D. nm cách khác nhau.

Choose the best answer for the following sentence:
As for me, I consider reading ___________ important part of __________ life. 
A. an / Ø                   
B. the / a               
C. Ø / the                  
D. an / a

Choose the best answer for the following sentence:
A shoe of leather is a _____________________. 
A. leather shoe                
B. shoed leather                  
C. shoe leather              
D. skinned leath

Choose the best answer for the following sentence:
If you ___________ time, please write to me. 
A. have            
B. had               
C. have had          
D. has

Choose the best answer for the following sentence:
She told me that she'd rather ___________ on the committee. 
A. not to serve                   
B. not serving
C. not serve                 
D. serving not

Choose the best answer for the following sentence:
He always prevents me _________ doing my duty.
A. of                
B. from             
C. with                  
D. against

Choose the best answer for the following sentence:
''When _____________?''
“In 1928.” 
A. penicillin was invented                     
B. did penicillin invented
C. was penicillin invented                
D. did penicillin invent

Choose the best answer for the following sentence:
______________ weapons have made more contribution to poaching and killing wild animals. 
A. Huge                 
B. Light                    
C. Advanced                  
D. Commercial

Choose the best answer for the following sentence:
Studying abroad can be very different form studying in your country. For example, in most schools in the UK, ______________ sport is encouraged.
A. join in
B. participation in
C. getting on
D. joining

Choose the best answer for the following sentence:
Thanks to the advances in _____________ research, people now live a better and longer life. 
A. science              
B. scientific                    
C. scientist               
D. scientifically