Some 250 million years ago, the earth suffered the greatest biological crisis in its history. Around 95% of all living species died out--a global catastrophe far greater than the dinosaurs' demise 65 million years ago. How this happened remains a mystery. But there are many competing theories...
However, the idea that there is an especially intense “Late Heavy Bombardment”between about 4 and 3.8 billion years ago, whichobliterates any life,no longer seems to be true. This means life may have begun in the first few hundred million years of Earth’s existence. 4.4 billion years ag...
根据"there has been life on the earth"可知,这里用的是现在完成时态,结合题目要用介词来填空,for+一段时间,since+时间点或者从句;hundreds of millions of years指的是一段时间,因此应用介词for。故填:for。【思路点拨】科学家们认为地球上的生命已经存在了数亿年。【解题思路】理解题干,结合语境,填写正确...
Passage One Animal life first appeared on the earth about 400 million years ago. Through the passing millennia, thousands of animal species have come and gone. Until recently, this process was gradual, the result of changes in climate, in habitat, or in the genes of the animals themselves. ...
Life began on earth million of years ago. Though there are (16) beings (17) opportunity given by existence, by looking beyond their desires. Life can be used,
The usual way is on the back of a mule. 现在,我们已到了离大峡谷缘下面 大约500 英里的地方 Here, we're about 500 feet below the lip of the canyon. 这里的岩石已经有两千万年了 Already the rocks are about 200 million years old. 这里还没有哺乳动物 但是已经有了一些四脚的陆地动物 ...
Scientists think that there has been life on Earth for years. A. millions B. millions ofC. million ofD. million
百度试题 结果1 题目Life started on the Earth___( million ) of years ago . 相关知识点: 试题来源: 解析 略 反馈 收藏
Ⅲ.综合填空Scientists think that there has been life on the earth for hundreds of millions of years.However, we 1.( not find )life on any other planets yet.The earth is a planet and it 2.(go) around the sun. Seven other planets also go around the sun.None of them has3.environment...
-___ years,I think.( ) A. 5 millions B. 5 millions of C. Million of D. Millions of试题答案 在线课程 分析 --生命存在地球上有多少年了?--我认为有数百万年. 解答 答案:D.million"百万"的用法是:如果前面有具体的数字,就不能用复数,也不能加of,故排除AB;如果没有具体数字,就要用复数,并跟...