第 16 至 20 題為題組 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. 【題組】17. (A) may be (B) would be (C) must have been (D) could have been