Nguyên nhân chủ yếu gây hiệu ứng nhà kính là chất khí
A. CO2 tăng trong khí quyển.
B. CH4 tăng trong khí quyển.
C. NO2 tăng trong khí quyển.
D. CFC tăng trong khí quyển.

Choose the best answer for the following sentence:
I haven't heard from Maria _____________ .
A.  since many months before                
B.  for many months 
C. for many months ago               
D. since a long time

Choose the best answer for the following sentence:
"We have been receiving reports of an alarming rate of malnutrition in southern Somali regions, where thousands of children are ______________ death," said Health Minister Isse Weheliye. 
A. in terms of                     
B. with respect to
C. on the verge of                    
D. in relation to

Choose the best answer for the following sentence:
On entering his old house, I _________ my head on a low beam. 
A. minded                    
B. knocked              
C. touched               
D. put

Choose the best answer for the following sentence:
The desert is very hot and dry, _____________.
A. so few plants and animals live there
B. therefore few plants and animals live there
C. however few plants and animals live there
D. but few plants and animals live there so

Choose the best answer for the following sentence:
________________ is the activity of swimming underwater using special breathing equipment.
 
A.  Synchronized swimming                      
B. Rowing  
C. Water polo                        
D. Scuba diving

Choose the best answer for the following sentence:
I would have prepared everything yesterday if I ____________ your message on onday. 
A. had received                    
B. have received
C. would have received                  
D. received

Choose the best answer for the following sentence:
“Can I borrow some money from you?”
“You’re already in debt _____________ me for sixty dollars.” 
A. for                 
B. to 
C. from  
D. by

Choose the best answer for the following sentence:
Few of them have made much ____________ in those branches of industry which give a variety and complexity to the affairs of a nation. 
A. increase            
B. progress                
C. growth                  
D. development

Choose the best answer for the following sentence:
______________, but now he's made a complete recovery.
A. My friend was bad being hurt in the accident
B. My friend had badly hurt in the accident
C. My friend has bad been hurt in the accident
D. My friend was badly hurt in the accident