Friction with the atmosphere will cause it to 18 and burn while traveling at high speed.
答案：(D) heat up
heat up（升溫、變熱）與後面的 burn 構成同一個過程：與大氣摩擦先生熱，進而燃燒；wear out（磨損、耗盡）、turn off（關掉）、break through（突破）都接不上 and burn 這個結果。
heat up 你大概只想到廚房裡的加熱——把飯菜熱一熱，後面一定跟著一個受詞。本句的 heat up 沒有受詞，是不及物的用法，意思是自己升溫、變熱。同一個片語，及物與不及物兩種用法都很常見，這一題考的正是後者。
四個選項都是動詞片語，文法上都接得上 cause it to ___，可見這一格考的是語意。線索是空格後面那個 and burn：空格與 burn 由 and 並列，兩者要是同一個過程裡先後發生的事。整句在講流星體高速穿過大氣層時與空氣摩擦——摩擦生熱，熱到極點就燒起來，先升溫再燃燒，順序完全吻合。
wear out（磨損、耗盡）雖然摩擦聽起來像會磨損，但它接不上 and burn，磨損不會導致燃燒。turn off（關掉）用在電器與開關上，流星體沒有開關可以關。break through（突破、穿透）表面上很誘人，因為流星體確實是穿過大氣層——但這一格與 burn 並列，要的是摩擦造成的結果，而穿透是它本來就在做的事，不是摩擦造成的。鑑別度 52，分開的是有沒有用 and 後面那個 burn 去回推空格。
heat up（升溫、變熱；及物時是把……加熱）、cause sth to V（導致某物……）、friction with（與……的摩擦）、wear out（磨損、耗盡）、break through（突破、穿透）、travel at high speed（高速前進）
Do you know the difference between the terms meteoroid, meteor, and meteorite in astronomy? Many people find these words confusing. However, the difference is all about their 16.
Meteoroids are far up in the sky. They are chunks of rock or metal that speed through space. Some are very large and may be hundreds of feet wide. Others 17 the size of a small stone. Most meteoroids travel around the sun in space and stay away from the Earth. However, sometimes a meteoroid will enter the Earth's atmosphere. Friction with the atmosphere will cause it to 18 and burn while traveling at high speed.
As a meteoroid begins to burn in the atmosphere, it leaves a streak of light. When this tail-like light is falling down toward the Earth, it is called a meteor, or a shooting star. Most meteors vaporize completely before they hit the ground.
If any meteor 19 its fiery journey through the atmosphere and lands on Earth, it is called a meteorite. Large meteorites can cause great explosions and much destruction on the surface of the Earth. 20 , Barringer Crater in the American state of Arizona, measuring 1,200 m in diameter and some 170 m deep, was produced by a meteorite impact.