Châu phi có khí hậu khô nóng, cảnh quan chủ yếu là hoang mạc, bán hoang mạc chủ yếu do
A. vị trí địa lí và địa hình quy định.
B. rừng bị tàn phá nghiêm trọng.
C. tác động của biến đổi khí hậu toàn cầu.
D. địa hình chủ yếu là núi cao đồ sộ.

Choose the best answer for the following sentence:
John said that at 9 o’clock the day before he ____________ the monthly report.
 
A. was writing 
B. has been writing   
C. had written  
D. had been writing

Choose the best answer for the following sentence:
Although my dad is busy with his work, he is willing to ____________ hand with the housework. 
A. give                
B. help                    
C. take                 
D. pass

Choose the best answer for the following sentence:
___________ is a hard cream-colored substance which forms the tusks of elephants. It is valuable and can be used for making carved ornaments.
A. Horn
B. Tooth
C. Ivory
D. Hide

Choose the best answer for the following sentence:
The children __________ all the orange juice yesterday after the heated match! We'll need to get some more. 
A. drunk                
B. have drunk                
C. drink                   
D. had drunk

Choose the best answer for the following sentence:
Do you have ___________________________ idea who could have borrowed your bicycle? 
A. some                 
B. no                 
C. neither           
D. any

Choose the best answer for the following sentence:
If I ___________ you, I’d save some of your lottery winning. 
A. be     
B. am           
C. were              
D. have been

Choose the best answer for the following sentence:
The train ________________ half an hour ago. 
A. has been leaving    
B. left       
C. has left     
D. had left

Choose the best answer for the following sentence:
''Where's Jack?'' ''He _______________ his girlfriend at the station. She ________________  at 12 o'clock.''
A. meets - is coming     
B. is meeting - comes  
C. meets - comes              
D. is meeting - is coming

Choose the best answer for the following sentence:
________________ energy in a tornado is enormous. 
A. The                  
B. A                   
C. An               
D. Some