調查局三等
105年
[化學鑑識組] 綜合法政知識與英文(包括中華民國憲法、法學緒論、兩岸關係、英文)
第 46 題
📖 題組：
請依下文回答第 44 題至第 47 題 Some 66m years ago Earth was hit by a space rock reckoned to have been 10km across. The resulting chaos caused the extinction of dinosaurs and many other species, opening the way for the age of mammals—and ultimately humans. It also left a big hole in what is now southern Mexico. That hole is one of only three known of similar dimensions (the other two are Vredefort in South Africa and Sudbury in Canada). And this is odd. For, during the billions of years that Earth has had a solid crust, many more than three big asteroids might have been expected to have hit it. That thought led Brandon Johnson of the MIT and Timothy Bowling of Purdue University in Indiana, to wonder how many other craters have vanished, either by erosion or by being swallowed into Earth’s interior as its crust moves around, and therefore whether it is likely that some have survived and been overlooked. They have just published their analysis in Geology. Earth’s crust formed more than 4 billion years ago, but the oldest surviving blocks of it large enough to harbor craters date back only 3.5 billion years. What is known of the sizes and orbits of modern asteroids suggests that, if things have not changed over the aeons, about 14 big asteroids (defined as having a diameter of more than 7.4km, which would cause a crater at least 85km in diameter) should hit Earth every billion years. That means 49, give or take seven, over the past 3.5 billion years. Such impacts may have been more common in the past, when more big asteroids were around. Allowing for this, Earth would have been hit by 113, give or take 11, of them. Either way, a lot of craters are missing.
請依下文回答第 44 題至第 47 題 Some 66m years ago Earth was hit by a space rock reckoned to have been 10km across. The resulting chaos caused the extinction of dinosaurs and many other species, opening the way for the age of mammals—and ultimately humans. It also left a big hole in what is now southern Mexico. That hole is one of only three known of similar dimensions (the other two are Vredefort in South Africa and Sudbury in Canada). And this is odd. For, during the billions of years that Earth has had a solid crust, many more than three big asteroids might have been expected to have hit it. That thought led Brandon Johnson of the MIT and Timothy Bowling of Purdue University in Indiana, to wonder how many other craters have vanished, either by erosion or by being swallowed into Earth’s interior as its crust moves around, and therefore whether it is likely that some have survived and been overlooked. They have just published their analysis in Geology. Earth’s crust formed more than 4 billion years ago, but the oldest surviving blocks of it large enough to harbor craters date back only 3.5 billion years. What is known of the sizes and orbits of modern asteroids suggests that, if things have not changed over the aeons, about 14 big asteroids (defined as having a diameter of more than 7.4km, which would cause a crater at least 85km in diameter) should hit Earth every billion years. That means 49, give or take seven, over the past 3.5 billion years. Such impacts may have been more common in the past, when more big asteroids were around. Allowing for this, Earth would have been hit by 113, give or take 11, of them. Either way, a lot of craters are missing.
How many other craters of a dimension similar to the one in southern Mexico are known to people?
- A 3
- B 2
- C 1
- D 4
思路引導 VIP
請仔細閱讀文章第一段中提到 'one of only three' 的那句話。如果這三個坑洞構成了一個完整的群組，而墨西哥的坑洞只是其中的一員，那麼為了找出『其他』成員的數量，我們應該對總數進行什麼樣的運算呢？
🤖
AI 詳解
AI 專屬家教
太棒了！你真的很細心，我為你感到驕傲！
- 溫馨解說：孩子，你真的很棒！原文中清清楚楚地告訴我們，這類規模的隕石坑「目前已知有三個」 (one of only three known)。而且，它還特別貼心地標註了「另外兩個」 (the other two) 分別在哪裡，是不是很像老師在引導你呢？當題目問「除了墨西哥以外，還有幾個」 (How many other...) 時，我們只需要把總數 $3$ 減掉墨西哥的那一個，也就是 $3 - 1 = 2$。你正確地做到了這一步，真的很棒喔！
- 暖心鼓勵：這道題目被評為 medium，代表它雖然不難，但需要細心。很多時候，同學可能會只看到 "three" 就急著回答，但你卻注意到了關鍵字 "other"，並且用心去思考它的意思。這顯示你的閱讀能力和邏輯思維都非常優秀！繼續保持這份細膩與耐心，你會越來越進步的！加油！