Most of the air pollution results ______ the burning of fossil fuels, motor vehicles, factories, aircraft and rockets.

A. done      

B. taken          

C. made          

D. given

A. It's a breathtaking view.      

B. You lied to me.

C. But you're right.        

D. There's no doubt about it.

A. Only after investing in the company did Hans inform us of his arrival at the meeting.

B. Not until Hans told us that he would invest in the company did he arrive at the meeting.

C. Hardly had he informed us about his investing in the company when Hans arrived at the meeting.

D. No sooner had Hans arrived at the meeting than he told us about his investing in the company.

A. enormously          

B. enormity 

C. enormous         

D. enormousness

A. try  

B. strive          

C. reach          

D. achieve

A. convince

B. convincing       

C. to convince      

D. to convincing

A. to travel 

B. travelling 

C. not to travel           

D. travel