________(39)
A.need         
B.must  
C.should  
D. would

Which of the following best describes the organization of this passage?
A.a chronological listing of the extinction of dinosaurs
B. a discussion of how an asteroid can destroy life
C.a listing of different ways that life on Earth could end
D.a comparison of asteroids and wildfire

Which of the following can be inferred from this passage?
A.Life is fragile and can be destroyed quickly.
B.Another asteroid will come to Earth soon.
C.Asteroids hit Earth every day.
D.Wildfires are more dangerous than asteroids.

The word "ones” UI the passage refers to ____.         
A.asteroids     
B.dinosaurs     
C.hours  
D.effects

What is the main topic of this passage?
A.how asteroids and comets are studied  
B.new research on environmental damage
C.how the dinosaurs became extinct       
D.the effects of an asteroid hitting the Earth

________(44)
A.do 
B.make         
C.keep     
D.put

________(43)
A.previous 
B.fast 
C.following
D. formerly

________(42)
A.gradually        
B.remarkably   
C.normally       
D.definitely

________(41)
A.yet  
B.but  
C.never 
D.still

________(40)
A.counting     
B.relying      
C.needing  
D.depending