However, the difference is all about their 16.
答案：(C) location
location（位置）呼應全文主軸——meteoroid 在太空中、meteor 在大氣層中燃燒、meteorite 落到地表，三個詞指的是同一個東西在不同位置時的名稱。size（大小）最誘人，但下一段說流星體有的可達數百英尺寬、有的只有小石頭大，大小在同一類裡差異極大，正好證明它不是區分三者的依據；weight（重量）、temperature（溫度）全文未提。
往下讀一段，馬上就看到 very large、hundreds of feet wide、the size of a small stone，滿眼都是在講大小，size 看起來簡直是為這一格準備的。但那幾句其實是反證：它們說的是同一類東西裡面，大小可以差到好幾百倍。既然同一類內部就差這麼多，大小當然不可能是用來區分三個名詞的依據。
四個選項都是名詞，文法上都放得進去，可見這一格考的是語意，只能往上下文找。這一句是全篇的主旨句：However, the difference is all about their ___.（然而，差別全在於它們的……）後面三段就是答案——第一段說 Meteoroids are far up in the sky（流星體在高空之中），第二段說進入大氣層燃燒時叫 meteor，第三段說撐過大氣層落到地面的叫 meteorite。同一個東西，只因為所在的位置不同就換了名字。四個選項裡只有 location 撐得起這個結構。
size 是命題端刻意設下的誘答，取材自空格後面出現過的字詞。眼熟不等於正確——看到一個剛剛好像看過的選項，那正是要停下來驗算的訊號，不是選它的理由。weight（重量）全篇從頭到尾沒有拿來比較過。temperature（溫度）只在 heat up and burn 那裡沾到一點邊，但那是流星體進入大氣層之後才發生的事，不是三個名詞的區別所在。
be all about sth（重點全在於……）、the difference between A and B（A 與 B 的差別）、find sth confusing（覺得……令人困惑）、far up in the sky（在高空之中）、speed through space（高速穿越太空）、hundreds of feet wide（數百英尺寬）
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.