Part Three Cloze
Directions:
There are ten blanks on the following passage. For each numbered bland, there are four choices marked A, B, C and D. choose the best one and mark your answer on the ANSWER SHEET with a single line through the center.
Fueled by weather, wind, and dry undergrowth, uncontrolled wildfires can burn acres of land-and consume everything in their way- in mere minutes.
__31__, more than 100,000 wildfires clear 4 million to 5 million acres of land in the U.S. very year. A wildfire moves at speeds of up to 23 kilometers an hour, consuming everything-trees, bushes, homes ,even humans- in its __32__.
There are three conditions that need to be __33__ in order for a wildfire to burn, fuel, oxygen, and a heat source. Fuel is any material __34__ a fire that will burn quickly and easily, including trees, bushes, even homes. Air supplies the oxygen a fire __35__ to burn. Heat sources help spark the wildfire and bring fuel to __36__ hot enough to start burning. Lightning, burning campfires or cigarettes, hot winds, and even the sun can all provide __37__ heat to spark a wildfire.
__38__ often harmful and destructive to humans, naturally occurring wildfires play a positive role in nature. They __39__ nutrients to the soil by burning dead or decaying matter. They remove diseased plants and harmful insects from a forest ecosystem （生态系统）. And by burning __40__ thick trees and bushes, wildfires allow sunlight to reach the forest floor, enabling a new generation of young plants to grow.
31. A After all B Above all C On average D In sum
32. A route B track C trace D path
33. A present B stable C fixed D favorable
34. A keeping B surrounding C causing D making
35. A needs B acquires C captures D meets
36. A materials B places C conditions D temperatures
37. A additional B excessive C sufficient D plentiful
38. A AS B Although C If D Whereas
39. A drive
