B
If you go to the Gulf of Mexico, you can see there is a big hole. It is called Chicxulub Crater (希克蘇魯伯隕石坑). Some people believe it was because of a huge asteroid (小行星) hitting this place, and the hit made dinosaurs die out millions of years ago.
This idea was first suggested in 1980. Later, scientists used special tools to find out what would happen if it was true. It showed that the asteroid could hit Earth at 40,000 miles per hour, leading to a big hole, a great tsunami (海嘯), earthquakes, and the melting (融化) of tons of rock. The hit took away millions of lives around the Chicxulub Crater.
The terrible story didn't stop there. Minutes later, hot rock started to rain down, and there was deadly dirt everywhere on the ground. Many animals were burnt to death. After several hours, a super-hot wind knocked down anything still standing.
In weeks, the sky was full of ash. Days became nights. This covered the sunlight for months or even years. Many plants died first. Then lots of animals died too because of food shortage, including almost all dinosaurs.
Although this idea sounds possible, the question of how dinosaurs died out remains unsolved scientifically. But as scientists discover more dinosaur fossils, we may know the truth one day.
( )6. What does the underlined word it in Paragraph 2 refer to?
A. The thought that the asteroid made dinosaurs die out.
B. The fact that Chicxulub Crater is in the Gulf of Mexico.
C. The truth that all dinosaurs died out millions of years ago.
D. The idea that a rock from space made a big hole on Earth.
( )7. According to the scientist, what happened when the asteroid hit Earth?
A. The hit made lots of rock melt.
B. Millions of lives were lost in Mexico.
C. A big hole appeared in North America.
D. The asteroid hit Earth at 40,000 miles per second.
( )8. According to the idea, what was the reason for the death of almost all dinosaurs?
A. Ash and dirt.
B. No sunlight.
C. Food shortage.
D. The asteroid's hit.
( )9. Which of the following statement is TRUE?
A. Hours later, animals died because of harmful gases.
B. We will surely know the truth from dinosaur fossils.
C. The dirt after the hit didn't hurt animals on the ground.
D. There isn't a scientific reason for the dinosaur's die-off.
( )10. Where can you probably find this passage?
A. In a storybook about dinosaurs.
B. In an encyclopaedia of animals.
C. In a science book about space.
D. In a travel magazine about Mexico.
答案：6.D
解析：第二段第一句提到 “這個觀點（小行星撞擊導致恐龍滅絕）于 1980 年首次被提出”，隨后 “Later, scientists used special tools to find out what would happen if it was true”（之后，科學家用特殊工具研究若 “它” 為真會發生什么）。結合上下文，“it” 指代的是前文 “小行星撞擊地球形成希克蘇魯伯隕石坑” 這一具體事件（即 “來自太空的巖石在地球上砸出大洞”），而非 “恐龍滅絕” 這一結果。A 選項側重 “恐龍滅絕” 的結論，B、C 與上下文無關，故選 D。
7.A
解析：根據第二段“the asteroid could hit Earth at 40,000 miles per hour, leading to... the melting of tons of rock.”可知，撞擊導致大量巖石融化，A選項正確。B選項“墨西哥失去數百萬生命”文中是“around the Chicxulub Crater”，并非整個墨西哥；C選項“北美出現大洞”文中未提及地點是北美；D選項“每秒40,000英里”錯誤，是“每小時40,000英里”。
8.C
解析：根據第四段“Many plants died first. Then lots of animals died too because of food shortage, including almost all dinosaurs.”可知，恐龍滅絕的直接原因是食物短缺，C選項正確。A選項“火山灰和泥土”、B選項“沒有陽光”是導致植物死亡的原因，進而導致食物短缺；D選項“小行星撞擊”是最初原因，但不是恐龍死亡的直接原因。
9.D
解析：根據最后一段“the question of how dinosaurs died out remains unsolved scientifically.”可知，恐龍滅絕的原因在科學上尚未解決，即還沒有科學的解釋，D選項正確。A選項“幾小時后動物因有害氣體死亡”文中是“burnt to death”和“super-hot wind”；B選項“我們一定會從恐龍化石中知道真相”文中是“may know”，并非“surely”；C選項“撞擊后的泥土沒有傷害地面動物”與第三段“there was deadly dirt everywhere on the ground. Many animals were burnt to death.”矛盾。
10.A
解析：文章主要討論恐龍滅絕的原因（小行星撞擊理論），與恐龍相關，最可能出現在關于恐龍的故事書中，A選項正確。B選項“動物百科全書”范圍太廣；C選項“太空科學書”重點在太空，而本文重點是恐龍滅絕；D選項“墨西哥旅游雜志”與主題無關。
